A silicon phased array based LiDAR device that measures a distance using a quasi-frequency modulation is disclosed. A LiDAR device according to an exemplary embodiment of the inventive concept includes a light source that generates an optical signal, an optical modulator that generates a first optical signal having a quasi-frequency whose a modulation frequency constantly varies with time by modulating a light intensity of the optical signal, an optical splitter that splits optical power of the first optical signal into a reference optical signal and a transmit (Tx) optical signal, an optical transmitter that receives and emits the Tx optical signal toward an object, an optical receiver that receives a receive (Rx) optical signal reflected from the object and transfers the Rx optical signal, an optical coupler that mixes the reference optical signal and the Rx optical signal, a balanced photodetector that detects an intermediate frequency from the optical signal transferred from the optical coupler and a distance calculator that obtains distance information by measuring the intermediate frequency.