An optical module including a plurality of laser diodes and outputting optical beams emitted from the laser diodes includes a radiator unit for radiating heat and a case enclosing the optical module. The case has a first attachment surface to which a red laser diode is attached, a second attachment surface to which a green laser diode is attached, and a corner part where the first and second attachment surfaces intersect with each other. The optical module has a first attachment part, for connecting the case to the radiator unit, in the vicinity of the corner part.