To reduce power consumption while validating the light control of high resolution.

At a time t0, the initial phase of a first light control signal S1 to be transmitted to a first laser light source unit is defined as a first time Ta, and the initial phase of a second light control signal S2 to be transmitted to the second laser light source unit is defined as a second time Tb, and the phase of each of a first light control signal S1 and a second light control signal S2 is shifted only by a difference between the second time Tb and the first time Ta, that is, the first time Ta.