A fixing structure wherein impact transmitted to a housing is efficiently transmitted to a circuit board and strain etc. generated at the housing are not transmitted to the circuit board. The fixing structure includes a circuit board mounting electronic devices, a housing storing the circuit board in the inside, and a plurality of board mounting seats provided at the housing for fixing the circuit board. Part of the plurality of board mounting seats rigidly mount the circuit board to the housing. Due to this, the impact is transmitted well to the electronic devices. The remaining board mounting seats are formed so as to flexibly mount the circuit board to the housing. Due to this, the strain generated at the housing is no longer transmitted to the circuit board and destruction of the circuit board can be prevented.