The invention provides a laser scanner, which comprises a light projecting unit for irradiating a distance measuring light, a light receiving unit for receiving a reflected distance measuring light, a distance measuring unit for performing a distance measurement based on a light receiving signal, a rotary deflecting unit for performing a rotary irradiation of the distance measuring light, and an arithmetic control unit, wherein the arithmetic control unit has a light receiving intensity judging component and a threshold value setting component, a light receiving intensity which is obtained by scanning the distance measuring light is inputted in advance to the threshold value setting component from the light receiving intensity judging component, the threshold value setting component sets a threshold value for detecting light receiving corresponding to the light receiving intensity, and the arithmetic control unit acquires a light receiving signal based on the threshold value and performs a distance measurement.