Laser survey instrument having a reflection light blocking means

摘要

A laser survey instrument, which is arranged on an optical axis of an emitted polarized irradiation light beam and is provided with a reflection light blocking means for blocking an incident reference light having a polarizing member and a +E,fra 1/4+EE wave birefringence member, whereby a harmful reflection light is blocked by the reflection light blocking means to improve detection accuracy of a signal light to be detected.