Disclosed is a distance measuring device configured to irradiate an object with light and receive reflected light therefrom to measure a distance from the object, including a light source device having at least one light-emitting part, a deflection part being provided rotatably around a predetermined axis line and having plural deflection faces configured to reflect light from the light source device toward the object, a reflection part being provided rotatably around the axis line and integrally with the deflection part and having plural reflection faces being provided to correspond to the plural deflection faces individually and reflecting a portion of light reflected from a corresponding deflection face and reflected from the object, and a light-receiving part having at least one light-receiving element configured to receive light reflected from the reflection part, wherein respective inclination angles of the plural deflection faces with respect to the axis line are mutually different.