To study the legal problems in contract law adopting the new technology called “Electronic agent” concluding contract on behalf of person. This study also aims to develop the application of contract law and approach to the proper solutions for further legal problems in Thailand. This research found that the applicable law of contract is not accordance with contract formation by electronic agent in practice. The expression by distance applies when the party can not express acceptance at that moment, while electronic agents’ responses suddenly on behalf of the party was accepted in commercial practice. The rule of mistake can not apply with error data message caused by technical or electronic agent system as the mistake is applied when the party’s belief is not accordance with the fact , including unequal bargain in negotiating process between consumer and electronic agent of entrepreneurs. This causes unfair contract term which consumers do have not opportunity to correct or prevent error data or consider the agreement before manifest assent. Moreover, using “Electronic agent" in Thai law may lead to misuse and wrongly interpret the law of agency. All of the above show that even Electronic Transaction Act B.E. 2544 attributes the legal effect of an offer and acceptance in the form of data message ,or the provisions in Civil and Commercial Code are general rule in contract law, these are not sufficient to consider and can not apply truly in contract formation by electronic agent. Its impacts destroy the confidence and the capacities in the legal effect of the contract concluded by electronic agent as well. Thus, The use of Electronic agent in electronic contract and electronic agent controlled by technical measures should be proposed in Thailand to promote technology development and enhance the growth of domestic commercial.
