Section 243 — Expert Witnesses and Their Opinions
Statutory text (Thai original)
ผู้ใดโดยอาชีพหรือมิใช่ก็ตาม มีความเชี่ยวชาญในการใด ๆ เช่น ในทางวิทยาศาสตร์ ศิลปะ ฝีมือ พาณิชยการ การแพทย์ หรือกฎหมายต่างประเทศ และซึ่งความเห็นของผู้นั้นอาจมีประโยชน์ในการวินิจฉัยคดี ในการสอบสวน ไต่สวนมูลฟ้องหรือพิจารณา อาจเป็นพยานในเรื่องต่าง ๆ เป็นต้นว่า ตรวจร่างกายหรือจิตของผู้เสียหาย ผู้ต้องหา หรือจำเลย ตรวจลายมือทำการทดลองหรือกิจการอย่างอื่น ๆผู้เชี่ยวชาญอาจทำความเห็นเป็นหนังสือก็ได้แต่ต้องส่งสำเนาหนังสือดังกล่าวให้ศาลและคู่ความอีกฝ่ายหนึ่งทราบ
และต้องมาเบิกความประกอบหนังสือนั้น เว้นแต่มีเหตุจำเป็น
หรือคู่ความไม่ติดใจซักถามผู้เชี่ยวชาญนั้น ศาลจะให้รับฟังความเห็นเป็นหนังสือดังกล่าวโดยผู้เชี่ยวชาญไม่ต้องมาเบิกความประกอบก็ได้ในกรณีที่ผู้เชี่ยวชาญต้องมาเบิกความประกอบ
ให้ส่งสำเนาหนังสือดังกล่าวต่อศาลในจำนวนที่เพียงพอล่วงหน้าไม่น้อยกว่าเจ็ดวันก่อนวันเบิกความเพื่อให้คู่ความอีกฝ่ายหนึ่งมารับไปในการเบิกความประกอบ ผู้เชี่ยวชาญจะอ่านข้อความที่เขียนมาก็ได้
English translation
Any person who, whether by profession or not, has special expertise in any matter, such as in science, art, craft, commerce, medicine, or foreign law, and whose opinion may be of use in deciding the case, may, in the investigation, preliminary hearing, or trial, be a witness on various matters, for example examining the body or mind of the injured person, the accused, or the defendant, examining handwriting, conducting experiments, or performing other tasks. An expert may render an opinion in writing, but must send a copy of that writing to the court and to the other party, and must appear to give evidence in support of it, unless there is a necessary cause or the parties do not wish to question the expert, in which case the court may admit the written opinion without the expert having to appear in support. Where the expert must appear to give evidence in support, a sufficient number of copies of the writing shall be submitted to the court not less than seven days in advance of the day of testimony, so that the other party may collect them. In giving evidence in support, the expert may read from the text he has written.
This English translation is provided for reference only and has not yet been firm-verified — always rely on the Thai original.
Firm annotation
Section 243 opens Book 5, Chapter 5 on special experts and defines who may serve as an expert witness and how their opinions are received. Expertise may be professional or not, spanning science, art, craft, commerce, medicine, and foreign law, and typical tasks include physical or mental examinations, handwriting analysis, and experiments. The section allows a written expert opinion but, as a rule, the expert must appear to give supporting testimony (paragraph two) so the opinion can be tested by cross-examination; this may be dispensed with for necessary cause or where the parties do not wish to question the expert. A seven-day advance-copy requirement ensures fairness. The courts have accepted expert evidence such as aerial-photograph interpretation, and have held that failure of the examiner to testify may be cured where another witness confirms the examination and result.
Why this matters in practice
Expert evidence often decides technical criminal cases (forensics, medical causation, questioned documents). Remember the default: the expert should appear so you can cross-examine, and copies of the report must reach you at least seven days before testimony. If the other side tries to put in a bare written report, consider whether to insist the expert attend. Equally, weaknesses in an opposing expert's method are fertile ground for challenge. Instructing your own qualified expert early, with a lawyer, can be pivotal.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 5206/2559 (2016)
An expert, such as an aerial-photograph interpreter, is a recognised category of evidence under the Code, and where the expert testifies before the trial court in accordance with Section 243, and the scientific work was carried out to proper standards by qualified persons, the evidence is lawfully received.
An aerial-photograph interpreter testified about the interpretation of aerial photographs. The Supreme Court held she was an expert, a recognised type of evidence under the Code, whose testimony before the trial court complied with Section 243, and that the underlying scientific work (photography, survey, mapping) was done to proper academic standards by qualified persons, so the report and testimony were properly received.
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Supreme Court Judgment No. 2234/2538 (1995)
Even if the prosecution does not call the examiner to testify in support of an expert examination report under Section 243 paragraph two, where the inquiry official testifies confirming the exhibit was sent for expert examination and found to be heroin, that evidence can establish the substance's identity.
The prosecution did not call the person who examined the exhibits to support the examination report under Section 243 paragraph two. The Supreme Court held that because the inquiry official testified confirming that the exhibits had been sent to an expert for examination and were found to be heroin, the prosecution's evidence could establish that the exhibits were heroin as charged.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Frequently asked questions
Who can be an expert witness in a Thai criminal case?
Under Section 243, anyone with special expertise, whether professional or not, in fields such as science, medicine, handwriting, or foreign law, whose opinion may help decide the case, may serve as an expert witness.
Must an expert appear in court to support a written report?
As a rule yes, under Section 243 the expert must appear to give supporting evidence, unless there is a necessary cause or the parties do not wish to question the expert, in which case the written opinion may be admitted alone.