To enhance working efficiency and safety while allowing a bracket to be surely fixed in a simple structure.

A lateral groove and a longitudinal groove not parallel thereto are formed on both sides of an equipment body. A bracket is provided with a rail-shaped protrusion stripe which can be projected to inside and inserted into a lateral groove and with a longitudinal groove engaging member movable between an engaged state of being inserted into and engaged with the longitudinal groove and a disengaged state of being pulled out of the longitudinal groove. When fixing the equipment body to the bracket, the longitudinal groove engaging member of the bracket is inserted into the longitudinal groove after inserting the protrusion stripe of the bracket into the lateral groove of the equipment body, thereby coming into the engaged state. When removing the equipment body from the bracket, the lateral groove of the equipment body is pulled out of the protrusion stripe of the bracket to be removed therefrom after pulling the longitudinal groove engaging member of the bracket out of the longitudinal groove of the equipment body to come into the disengaged state.