A semiconductor laser (41) is fixed onto a base part (22) with a submount (32) and a reference optical axis (5) is determined by the semiconductor laser (41). A groove (222) having a U-shaped section is formed on a bonding part (221), and solder (31) is applied in the groove (222) and melted and a collimator lens (42) supported by a supporting arm (61) is moved to the groove (222). A light beam emitted from the semiconductor laser (41) is guided through the collimator lens (42) to an image pickup part (7), where an image representing the state of the light beam is acquired. The collimator lens (42) is positioned with respect to the reference optical axis (5) on the basis of the image and fixed onto the base part (22) out of contact therewith, with the solder interposed therebetween. This simplifies a structure of an optical element module (11) in which the collimator lens (42) is positioned with respect to the reference optical axis (5) with high accuracy.