Abstract: A service system offers information of an invitation of a public contribution and/or a prize contest by using a cellular phone, a personal digital assistant or a computer terminal machine. A user can easily participate in the system. The user is individually provided with proper information of the invitation of public contribution and/or the prize contest, and can apply for the information, by on-line registering basic information of the user through a cellular phone, a personal digital assistant, or a computer terminal machine connectable to the Internet, by carrying out a referring process on-line by using the proper information. The user is permitted access to a plurality of information of invitation of public contributions and/or prize contests on the Internet.