Section 163 — Amending the Charge or the Plea
Statutory text (Thai original)
เมื่อมีเหตุอันควร โจทก์มีอำนาจยื่นคำร้องต่อศาลขอแก้หรือเพิ่มเติมฟ้องก่อนมีคำพิพากษาศาลชั้นต้น ถ้าศาลเห็นสมควรจะอนุญาตหรือจะสั่งให้ไต่สวนมูลฟ้องเสียก่อนก็ได้ เมื่ออนุญาตแล้วให้ส่งสำเนาแก้ฟ้องหรือฟ้องเพิ่มเติมแก่จำเลยเพื่อแก้ และศาลจะสั่งแยกสำนวนพิจารณาฟ้องเพิ่มเติมนั้นก็ได้เมื่อมีเหตุอันควร จำเลยอาจยื่นคำร้องขอแก้หรือเพิ่มเติมคำให้การของเขาก่อนศาลพิพากษา ถ้าศาลเห็นสมควรอนุญาต ก็ให้ส่งสำเนาแก่โจทก์
English translation
When there is reasonable cause, the plaintiff has the power to file a motion with the court to amend or add to the charge before the judgment of the court of first instance. If the court thinks fit, it may grant the motion, or may order a preliminary examination to be held first. Once granted, a copy of the amended or additional charge shall be served on the defendant for his defence, and the court may order the additional charge to be tried in a separate case. When there is reasonable cause, the defendant may file a motion to amend or add to his plea before the court delivers judgment. If the court thinks fit to grant it, a copy shall be served on the plaintiff.
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 provides symmetric powers for both sides to amend their pleadings, the plaintiff's charge and the defendant's plea, before the court of first instance gives judgment. It requires reasonable cause and the court's discretion, and it protects the other side by requiring service of the amendment so it can respond. The recurring point in the case law is the deadline: an amendment of the plea must be made before the trial court's judgment, so a defendant cannot switch a plea from denial to a guilty plea at the appeal or Supreme Court stage. It works alongside Section 164, which sets the outer limit that an amended charge must not prejudice the defence.
Why this matters in practice
The practical rule to remember is timing. If a defendant wants to change a plea, for example from denial to a guilty plea to seek a reduced sentence, it must happen before the first-instance judgment; trying to do so on appeal or at the Supreme Court will not be accepted and is treated only as abandoning the earlier defence. Plaintiffs, too, must move to amend the charge before judgment. Missing this window can cost a party a key procedural option, so raise any needed amendment early.
Supreme Court decisions interpreting this section
-
Supreme Court Judgment No. 2966/2568 (2025)
Under Section 163 paragraph two, a defendant's motion to amend or add to the plea must be made before the trial court's judgment. A request to amend the plea filed at the Supreme Court stage cannot be granted.
The defendant filed a motion at the Supreme Court stage that in substance sought to withdraw the earlier plea and give a new one. The Court quoted Section 163 paragraph two and held that amending a plea must be done before the trial court's judgment, so it could not be done on appeal to the Supreme Court.
-
Supreme Court Judgment No. 2934/2566 (2023)
Amending a plea from denial to a guilty plea must be done before the trial court's judgment under Section 163 paragraph two. A guilty plea offered only at the Supreme Court stage is treated merely as accepting the facts without contesting the appellate court's ruling.
The defendants sought to change their plea to guilty at the Supreme Court stage. The Court held this was an amendment of the plea that must be made before the trial court's judgment under Section 163 paragraph two, so it could not be done and only amounted to accepting the facts as found by the appellate court.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Frequently asked questions
Can a defendant change their plea from not guilty to guilty in Thailand?
Yes, but under Section 163 paragraph two it must be done before the court of first instance delivers judgment. A plea cannot be changed on appeal or at the Supreme Court stage.
Can the prosecution amend the charge after filing?
Yes. Under Section 163 the plaintiff may, with reasonable cause and the court's leave, amend or add to the charge before the first-instance judgment, and the amendment is served on the defendant to respond.