The present disclosure relates to a laser ranging device. The laser ranging device includes an encoded chassis, a rotary disc, a first barrier ring on the rotary disc and/or a second barrier ring on the encoded chassis. The encoded chassis includes a rotary bin and a plurality of ranging teeth disposed at intervals on the periphery of the rotary bin. The rotary disc is mounted within the encoded chassis and is rotatable within the rotary bin when the rotary disc is driven. The first barrier ring is disposed at the edge of the bottom surface of the rotary disc and the second barrier ring is disposed at the periphery of the ranging teeth, and the first barrier ring is located at the periphery of the ranging teeth after the rotary disc is mounted to the encoded chassis.