Section 164: Amendment Must Not Prejudice the Defence
Statutory text (Thai original)
คำร้องขอแก้หรือเพิ่มเติมฟ้องนั้น ถ้าจะทำให้จำเลยเสียเปรียบในการต่อสู้คดี ห้ามมิให้ศาลอนุญาต แต่การแก้ฐานความผิดหรือรายละเอียดซึ่งต้องแถลงในฟ้องก็ดี การเพิ่มเติมฐานความผิดหรือรายละเอียดซึ่งมิได้กล่าวไว้ก็ดี ไม่ว่าจะทำเช่นนี้ในระยะใดระหว่างพิจารณาในศาลชั้นต้น มิให้ถือว่าทำให้จำเลยเสียเปรียบ เว้นแต่จำเลยได้หลงต่อสู้ในข้อที่ผิดหรือที่มิได้กล่าวไว้นั้น
English translation
As for a motion to amend or add to the charge, if it would put the defendant at a disadvantage in defending the case, the court shall not grant it. However, amending the offence charged or the particulars that must be stated in the charge, or adding an offence or particulars not previously stated, whenever done during the trial in the court of first instance, shall not be regarded as putting the defendant at a disadvantage, unless the defendant has been misled in defending against the point that was wrong or was not stated.
This English translation is provided for reference only and has not yet been firm-verified. Always rely on the Thai original.
Firm annotation
This section sets the substantive limit on the amendment power granted by Section 163. The guiding principle is fairness to the defence: the court must reject any amendment that would prejudice the defendant. It then creates a broad allowance for correcting or adding the offence charged or required particulars during the first-instance trial, which is not treated as prejudicial in itself, with the single safeguard that the defendant must not have been misled into defending the wrong point. A settled application in the case law is that an amendment presupposes an already-complete original charge, so it cannot be used to introduce a genuinely new claim, such as a civil claim not brought with the original criminal charge.
Why this matters in practice
For defendants, the key question is whether an amendment surprised you into defending the wrong case; if it did not, the court can allow a change to the offence or particulars mid-trial. For plaintiffs, remember that amendment builds on a complete original charge and cannot smuggle in a brand-new claim, so a civil claim linked to the offence must be brought with the criminal charge from the start, not added later. If an amendment materially changes the case against you, be ready to show you were genuinely misled.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 4081/2564 (2021)
An amendment or addition to the charge under Section 164 presupposes that the original charge is already complete. Where only a criminal charge was filed, the plaintiff cannot later add a motion imposing civil liability, because a civil claim connected to the offence must be brought together with the criminal charge from the outset.
After filing only a criminal charge and after the charge was accepted and the defendant had pleaded, the plaintiff sought to amend the charge to add civil liability. The Court held that amendment under Section 164 requires a complete original charge and cannot be used to raise a new civil claim, so the amendment allowing it was improper.
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Supreme Court Judgment No. 11066/2558 (2015)
Because a civil claim connected to a criminal case must be filed together with the criminal charge, a plaintiff who filed only a criminal charge cannot, after the charge is accepted and the defendant has pleaded, amend the charge under Section 164 to add civil liability, as the original charge must already be complete.
The plaintiff had filed only a criminal charge, and after acceptance and the defendant's plea, moved to add a civil claim for repayment of money. The Court held that amendment under Section 164 requires an already-complete original charge and cannot introduce a new civil claim, since such a claim had to be brought with the criminal charge from the start.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Cited in 53 Supreme Court decisions (1940 to 2023)
Selected citing decisions
- Decision 1/2566 (2023)
- Decision 2/2566 (2023)
- Decision 5234-5238/2566 (2023)
- Decision 8429/2559 (2016)
- Decision 11066/2558 (2015)
- Decision 10758/2556 (2013)
- Decision 9860/2552 (2009)
- Decision 6996/2551 (2008)
This list is selected automatically, weighted towards judgments that turn on this section rather than ones that merely recite it when passing sentence. It has not yet been reviewed by the firm.
Most often cited alongside
- Section 163 29
- Section 158 19
- Thai Penal Code s. 91 9
- Thai Penal Code s. 78 9
- Thai Penal Code s. 83 8
- Thai Penal Code s. 90 6
Sections that appear in the same judgments as this one most often. The figure is the number of decisions.
Counted across the firm's corpus of 83,652 Supreme Court decisions, 1921 to 2026. The count is complete; the stated year range trims rare outliers so it describes where the citations actually sit. These figures are computed by us and are not official court statistics. How we count these, and what we measured
Frequently asked questions
When can a court refuse to allow a charge to be amended?
Under Section 164 the court must refuse an amendment that would put the defendant at a disadvantage in defending the case, unless correcting or adding the offence or particulars during the first-instance trial did not mislead the defendant.
Can a civil claim be added to a criminal charge by amendment?
No. Case law under Section 164 holds that an amendment presupposes a complete original charge and cannot introduce a new civil claim; a civil claim connected to the offence must be filed together with the criminal charge from the start.
Related guides on ThaiLawOnline
Cite this section
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Plain citation
Criminal Procedure Code, s. 164 (Thailand) -
Academic citation
Criminal Procedure Code (Thailand), s. 164. ThaiLawOnline, https://www.thailawonline.com/thai-criminal-procedure-code/section-164/ (accessed 11 August 2026). -
Thai citation
ป.วิ.อ. มาตรา 164 -
Permalink
https://www.thailawonline.com/thai-criminal-procedure-code/section-164/ -
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<blockquote cite="https://www.thailawonline.com/thai-criminal-procedure-code/section-164/"><p>As for a motion to amend or add to the charge, if it would put the defendant at a disadvantage in defending the case, the court shall not grant it. However, amending the offence charged or the particulars that must be stated in the charge,…</p><footer>Criminal Procedure Code, s. 164 (Thailand) — <a href="https://www.thailawonline.com/thai-criminal-procedure-code/section-164/">ThaiLawOnline</a></footer></blockquote>
The Thai text is authoritative. The English is an unofficial translation by ThaiLawOnline, free to reuse with attribution.