PURPOSE: To lessen screwing in fixing to fixing part surfaces of an apparatus and the man-hour for the screwing.

CONSTITUTION: The opposite mounting surfaces 12, 12b of an apparatus casing 12 are bored with mounting holes 13 and rising supporting piece parts 14a, 15a of mounting brackets 14, 15 for fixing the apparatus 11 to the fixing part surface are projectingly provided with engaging projectors 16, 17. These engaging projectors 16, 17 are inserted and engaged into and with the mounting holes 13 of the apparatus casing 12, by which the mounting brackets 14, 15 are mounted to the apparatus casing 12.