To provide a mounting device which enables people in general to fix a monitoring camera or the like without boring a large hole in a ceiling or wall, which can be more strongly fixed than the case that a desired device is disposed by a suction member or an adhesive only, which causes the less deterioration of fixing strength due to aging, and which is able to resist earthquakes or vibration.

This device comprises three expansible rod members 3 that are fixed to each other at their both ends by connecting members 4, pressed to the ceiling 30 and two walls 28 and 29, and extended. A base seat 2 is fixed to the expansible rod members 3, and the desired device 32 such as the monitoring camera is fixed to the base seat 2.