To provide a prize contest system for rejecting unfair application for a closed prize contest using the Internet.

This prize contest system 1 comprises an application receiving means 11 that receives an application to the prize contest through the Internet 2 and requests the applicant to input a proper code W by commodity previously provided for commodities when receiving the application, a determining means 12 for determining whether or not the application is a normal application based on the code inputted by the applicant, and a proper code setting means 13 by commodity for setting a code difficult to estimate a proper code W by commodity attached to the other commodity as the proper code W by commodity. Thus, an unfair application with an estimated code is easily determined, and is prevented to be permitted as a normal application in error.