To identify colors at multiple measurement paints with a simple configuration and in a short time.

An optical axis direction change optical system 3 comprises a scanning mirror 31, a motor 32 and reflection mirrors 33-37. The scanning mirror 31 is held, while a rotation around a specified spindle is permitted, with a holding part 32a directly connected to a motor shaft of the motor 32. The reflection mirrors 33-37 are distributed around the spindle in its rotation direction, and so assigned as to be parallel to a reflection surface of the scanning mirror 31 when each reflection surface is at a specified rotation angle position. Thus, the projected light which was reflected on the scanning mirror 31 at each rotation angle position and then reflected on each reflection mirrors 33-37, made incident an a sample 4 to parallel each other.