A device mounting apparatus that allows the orientation of a device to be easily adjusted alone. The device mounting apparatus is mounted with a device. A mount includes a seat fixed to a base, and a rotation mechanism portion that is supported by the seat and can change the orientation of the device relative to the seat. An adjustment jig is attachable to and detachable from the mount and includes a driving unit driven by operation. The rotation mechanism includes a supporting unit that supports the device, a changing unit that changes the orientation of the rotation mechanism according to driving of the adjustment jig when the adjustment jig is mounted to the mount, and brakes that fix the orientation of the rotation mechanism when the adjustment jig is detached from the mount.