VEHICLE-MOUNTED DEVICE

A device base which is part of a device main body includes a support fixing portion having a support member fixed thereto and the base main body portion which is the other portion of the support fixing portion. A preferential rupture portion is formed between the support fixing portion and the base main body portion. The rupture fixed portion having the support fixing portion fixed to the support member has a hook member attached thereto, which is formed with a metal plate having elasticity. A hooking portion at the front end of the hook member faces an inner side portion of the base main body portion. If the preferential rupture portion ruptures due to an impact force, the hooking portion is hooked to the inner side portion, and the device main body is prevented from falling down from the rupture fixed portion.