Studies problems concerning withdrawal and revocation of administrative acts. It can be separately considered between withdrawal and revocation of administrative acts by the administrations, and by the courts. Study the principles and effects of withdrawal and revocation of administrative acts. The research reveals that, before having the Administrative Procedure Act B.E. 2539, the withdrawal and revocation of administrative acts was one of the means given to the administration body to control the persons affected by the administrative act to comply with the provisions of law. Though there were some regulations allowing the withdrawal and revocation of administrative acts, to conform to the principle of legality of administrative act or the public welfare, there was no clear and definite rules in withdrawal and revocation of administrative acts and in protection of the involved persons against the damage caused by those acts. As a result, the renders with respect to the principle of legality of administrative acts, taking into account the principle of security of rights and the principle of the reliance of involved persons in the existence of administrative acts were legally defective. After having the Administrative Procedure Act B.E. 2539, the rules of withdrawal and revocation of administrative act have been laid down in consideration of the said three principles. Regarding the withdrawal and revocation of administrative acts by the court of justice, since Thailand does not have the administrative Court and law on Administrative Court, the Courts of Justice is accordingly the one who has the authority to make decisions on cases concerning the withdrawal and revocation of administrative acts. The Court mostly considers the withdrawal and revocation of administrative acts in reference to the concept of torts and thus applies to the Civil Procedure Code. The purpose of the tort law is to give remedy to the damagers, while, the propose of the withdrawal and revocation of administrative acts is to examine the legality of the administrative acts. As a result, the court of justice cannot completely examine the legality of administrative acts. Therefore, the study of this thesis is based on the comparison of French and German laws regarding withdrawal and revocation of the administrative acts. This would enable the Administrative Court, when established together with the enactment of the court procedure, to perform the efficient functions in examining and guarding the principle of legality of administrative acts.
