To provide a support device for an on-vehicle electronic apparatus capable of removing the on-vehicle electronic apparatus by easily operating with one hand.

A mobile navigation device 101 is led from upward to downward so that an elongated groove of the mobile navigation device 101 is inserted into a tenon 30 of a cradle 3, and an interference part 14 at a tip of a stopper plate 12 is engaged with the mobile navigation device 101 to be mounted on the cradle 3. When being detached, the mobile navigation device 101 is pulled with the cradle 3 in a first direction against a coil spring 33, and the interference part 14 is moved in a direction that recedes from a perpendicular abutting face 25 relatively to release an engagement relationship so as to be detached upward as it is. Accordingly, the mobile navigation device 101 can be detached from the support device with one hand.