To improve the stability of an adhesion state and the accuracy of position adjustment by making an adhesion part hardly deformable when gripping a holding member that holds a light receiving element and performing position adjustment.

A second holding member 12 has a base part 15, adhesion parts 12a provided on the base part 15 and grip parts 12b extending from the base part 15. The second holding member 12 that holds a photometric sensor 10 is filled into and stuck and fixed to a first holding member 11 that holds photometric lenses 9a, 9b, in a state where the relative position of the first and second holding members 11, 12 is adjusted. In a step of adjusting the relative position, the second holding member 12 is gripped at R-shaped parts 12d as gripping positions by an external energizing force whose center is on an optical axis C2, and the grip parts 12b are elastically gripped in a flat surface parallel to a light receiving surface 10a by bending the R-shaped parts 12d in a direction of the optical axis C2 by the energizing force.