Abstract: A pocket personal computer having improved battery compartment enclosing structures is disclosed. The battery compartment enclosing structures include a battery compartment defined in a rear side of the pocket personal computer for accommodating a battery therein, a battery compartment cap for enclosing the battery compartment and an unlocking means form unlocking the cap. The battery compartment has two positioning openings defined in a rear side wall of the compartment and a bulge inwardly formed on an inner face of a front side wall and the bulge has a slanted upper face and a flat lower face. The cap has two protrusions formed at a rear end thereof which can be received in the openings as the cap is positioned over the compartment and a latch downwardly formed at the front end of the cap and the latch has a slanted lower end and a depressed neck portion to cooperate with the bulge to lock the cap in position.