To detect a projected part projected from a storable range, during a parking operation into a mechanical type parking device, and to inform a user of it.

A vehicle 20 is driven in on a palette 18 on a cage 17 in a building 12 from a drive-in port 13 provided in a front sidewall 12a of the building 12 in the mechanical type parking device. A detecting sensor 15 is installed in a rear sidewall 12b of the building 12, to pass a laser beam 16 through an upper position of a boundary part in the storable range serving as lateral both-side part outer positions of the palette 18. The detecting sensor 15 is constituted to emit the laser beam 16 to be brought into a flat plane along a vertical direction, the laser beam 16 is emitted therein in parallel to outsides of both-side parts of the vehicle 20, and the projected part is detected in a range on a face of the laser beam 16.