A scanning mirror-based LiDAR device according to an embodiment of the present invention is characterized by comprising: a light source for generating laser pulses; a first collimation lens for converting the laser pulses to collimated light and emitting same; a scanning mirror which reflects emission light, emitted from the first collimation lens, toward a subject, and re-emits incident light reflected from the subject, by changing the angle of the light via one-way high-speed rotation scanning; a second collimation lens for focusing the light re-emitted from the scanning mirror by changing the angle via the high speed rotation scanning; a plurality of light receiving element arrays which are arranged in the direction perpendicular to the rotation axis of the scanning mirror, and which receive the light focused by the second collimation lens and generate the light as electrical signals; and a signal processing unit which uses the electrical signals, generated by the plurality of light receiving element arrays, to calculate the measurement distance and measurement time for the subject corresponding to the scanning angle of the scanning mirror. The period of the laser pulses emitted from the light source is shorter than the round-trip time-of-flight of the laser pulses corresponding to the maximum measurement distance of the subject.