A time-of-flight distance measuring device comprising: a light source that emits light, as emitted light, to illuminate a specified region; a light receiver that detects, as reflected light, the emitted light reflected by an object (78, 80, 80a, 80b) in the specified region; a first controller that controls the light source; a second controller that controls the light receiver; a calculator that calculates a distance to the object based on the reflected light detected by the light receiver; said device being characterized by a multipath detector that detects occurrence of a multipath error, wherein the specified region is divided into a plurality of sub-regions (R1, R2), the light source includes a plurality of emitting portions, each of the plurality of emitting portions illuminating a respective one of the plurality of sub-regions, the light receiver includes a plurality of receiving portions (74, 76) corresponding to respective ones of the plurality of emitting portions, each of the plurality of receiving portions being spaced away from each other to sense the reflected light reflected from the sub-region illuminated by the corresponding emitting portion, the first controller controls (i) a first emitting portion of the plurality of emitting portions to emit the emitted light as an amplitude-modulated waveform including an N th -order harmonic component of a fundamental frequency and (ii) a second emitting portion of the plurality of emitting portions to emit the emitted light as an amplitude-modulated waveform including an M th -order harmonic component of the fundamental frequency, wherein N and M are different positive integers, the second controller controls a particular receiving portion of the plurality of receiving portions corresponding to the first emitting portion of the plurality of emitting portions to be sensible to the N th -order harmonic component and the M th -order harmonic component, and the multipath detector detects occurrence of the multipath error when the particular receiving portion senses both the N th -order component and the M th -order component. a light source that emits light, as emitted light, to illuminate a specified region; a light receiver that detects, as reflected light, the emitted light reflected by an object (78, 80, 80a, 80b) in the specified region; a first controller that controls the light source; a second controller that controls the light receiver; a calculator that calculates a distance to the object based on the reflected light detected by the light receiver; said device being characterized by a multipath detector that detects occurrence of a multipath error, wherein the specified region is divided into a plurality of sub-regions (R1, R2), the light source includes a plurality of emitting portions, each of the plurality of emitting portions illuminating a respective one of the plurality of sub-regions, the light receiver includes a plurality of receiving portions (74, 76) corresponding to respective ones of the plurality of emitting portions, each of the plurality of receiving portions being spaced away from each other to sense the reflected light reflected from the sub-region illuminated by the corresponding emitting portion, the first controller controls (i) a first emitting portion of the plurality of emitting portions to emit the emitted light as an amplitude-modulated waveform including an N th -order harmonic component of a fundamental frequency and (ii) a second emitting portion of the plurality of emitting portions to emit the emitted light as an amplitude-modulated waveform including an M th -order harmonic component of the fundamental frequency, wherein N and M are different positive integers, the second controller controls a particular receiving portion of the plurality of receiving portions corresponding to the first emitting portion of the plurality of emitting portions to be sensible to the N th -order harmonic component and the M th -order harmonic component, and the multipath detector detects occurrence of the multipath error when the particular receiving portion senses both the N th -order component and the M th -order component.