The present invention relates to a game program rewrite 
system for supplying data of a game program of a plurality of terminal stations from a host 
station and writing the data in portable 
information storage media applied to game execution units in the terminal stations in response to requests, and a program rewrite 
system suitable for this game program supply 
system, and aims at enabling construction of a game-on-demand system including a number of terminal stations with no excess of requirement to equipment of a network or the data 
throughput of the host 
station. In order to attain the above object, a host 
station (1) supplies data of a game program to a terminal station (2) online through a communication network. The data of the game program is supplied to the terminal station (2) offline too. The data of the game program preserved in the terminal station (2) is written in a game execution storage medium (20) in response to a request of a user.