Abstract: A rearview mirror mounting apparatus for detachably mounting a rearview mirror onto a side portion of a vehicle body of a vehicle such as automobile, motorcycle and the like. Between a mounting seat formed on the rearview mirror and the vehicle body, there is provided an elastic connecting piece having an excessive length when the mounting seat is fixed to the vehicle body by a bolt or the like. One end of the connecting piece is retainably engagable with the mounting seat and the other end with the vehicle body. The connecting piece is contained within the rearview mirror mounting apparatus. Although, the rearview mirror is detachable from the vehicle body, it cannot be separated apart from the vehicle body any further than the length of the connecting piece since the connecting piece is retainably engaged at one end with the mounting seat of the rearview mirror and at the other end with the vehicle body.