A projector system of the present invention includes a projector 10 and a personal computer PC as an information terminal, which communicate with each other via a network connection. The projector 10 generates a password required for establishment of the network connection and projects the password on a screen SC. A user of the personal computer PC inputs the password projected on the screen SC. The password is used for authentication of the network connection between the projector 10 and the personal computer PC and cipher communication therebetween. This arrangement of the present invention enhances the convenience of the projector that is capable of establishing a network connection with the information terminal, while ensuring secrecy of communicating data.