A robbery-proof mechanism for a vehicle mounted electronic apparatus wherein a cover for covering the electronic apparatus is accommodated in the upper space of the electronic apparatus and can be driven by a small scale drive mechanism without moving the electronic apparatus. The robbery-proof mechanism includes: a frame mounted on the front of the vehicle mounted electronic apparatus, being rotative between a horizontal position and a vertical position; a cover capable of being inserted into a groove formed in the frame; a drive mechanism for driving the cover in the horizontal direction between a position in the groove of the frame and a position retracted from the frame; and a drive mechanism for driving an operation panel in the horizontal direction, wherein the frame is rotated to the horizontal position, the cover is then moved into the groove of the frame and the operation panel is moved backward, and the frame together with the cover is rotated to the vertical position to cover the operation panel with the cover.