A locking device for a compact computer or a small computer, in particular, a personal data accessory or a palm data accessory (hereinafter referred to as PDA), is presented. The invention also includes a blocking device which is connected with the locking mechanism and is convertible between an unlocking position and a locking position, the blocking device is adapted to be locked and secured by the locking mechanism. The blocking device is adapted to be set to the locking position and resist against the incline surface of the stand so as to lock and secure the PDA with the stand.