To prevent a burglar from committing a criminal act by instantly inflating an airbag toward an open space side of a passenger seat and the like in a vehicle for business use in which a crime prevention wall is mounted.

A security device body 5 is formed by the airbag 3 comprising blade-proof cloth and by an inflator for blowing out gas into the airbag 3 to inflate the airbag 3. Further, the security device body 5 is disposed in an upper direction of a support of the crime prevention wall 6 of a back surface of a driver in the vehicle for business use in which a crime prevention wall 6 is mounted, and a starting switch 10 for inflating the airbag 3 by starting the security device body 5 is mounted adjacent to a driver seat 7. This eliminates the gap between the driver seat 7 and open space 8 when the starting switch 10 is pressed and the airbag 3 is inflated.