To provide a portable low-cost gun shooting game device capable of performing a gun shooting game by only connecting the game device to a display device anywhere provided with the display device.

A game device main body 1 formed into the shape of a gun and provided with a built-in game soft is provided with an image generating unit 8 for generating an image to be displayed on a screen of the display device 3 for displaying the screen with a raster scanning method, a position detecting unit 10 for detecting an impact position on the screen when pulling a trigger for shooting, and a judging unit 11 for judging whether a target is shoot or not on the basis of the impact position and a position of the target on the screen. The display device 3 and the game device main body 1 are connected to each other through a signal cable 2.