Casing for reflection measurement device

摘要

A casing is provided for a reflection measurement device emitting a scanning beam and receiving an echo beam caused by reflection of the scanning beam at an object, and detecting a distance to the object in response to the received echo beam. The casing has a window for conducting a beam, and a protective member being transparent to the beam and covering the window from an inside. A predetermined range through which the beam passes is provided in the window. An interval between a lower edge of the beam pass range and a lower edge of the window is greater than an interval between opposing edges of the beam pass range and the window which differ from the lower edges thereof.