To shorten the time required for the selection while the simple maneuverability is realized when a desired alternative is selected.

The weapon switching processing is executed by a key operation to an upper key 1204a or a lower key 1204b. As the result of the weapon switching processing, the currently used weapon is switched to a corresponding use candidate weapon. When the key operation to the upper key 1204a is executed, the currently used weapon is switched to a first candidate weapon exhibited by a first candidate display section W22-1. On the contrary, when the key operation to the lower key 1204b is executed, the currently used weapon is switched to a second candidate weapon exhibited by a candidate display section W22-2.