A measuring device includes: a light source; an interference optical system that separates light into reference light and irradiation light, generates interference light by causing interference between the reference light and reflected light generated by reflection of the irradiation light on an object; a photodetector that receives the interference light and outputs a signal corresponding to an intensity of the interference light; and a processing circuit that controls the light source and generates and outputs data on a distance and/or velocity of the object based on the signal outputted from the photodetector, in which the processing circuit causes the light source to emit light having a frequency that changes with time within a first frequency range in a first mode, and causes the light source to emit light having a frequency that changes with time within a second frequency range different from the first frequency range in the second mode.