To provide an electronic safing system at the low cost without complicating a device structure of an air bag ECU whereby reliability of air bag movement can be secured and delay of processing can be prevented.

In an electronic component provided in an anti-theft ECU 10 constituted as a separate device from the air bag ECU 20, namely an anti-theft electronic safing microcomputer 12, permission of development of the air bag is determined based on the detection result of an anti-theft acceleration sensor 11a and an acceleration sensor 21a of the air bag ECU 20. When the anti-theft acceleration sensor 11a is used for safing, a detection sensitivity of the acceleration sensor 11a is switched to a detection sensitivity for the air bag development determination, for example around ±100 G by a sensitivity switch part 14 of the anti-theft ECU 10.