There is provided a technique in which alignment can easily be performed, a period for which the alignment adjustment is completed is shortened, and operability is improved. Alignment is performed using the apex of cornea as a reference by optical structures different from those of the light projection system and the light receiving system. An intersection point of optical axes of the light projection system and the light receiving system in the eye is set to a biological property measurement point in the eye which is shifted by a predetermined distance from the apex of cornea.