According to one embodiment, a laser drive circuit which supplies a drive current to a laser element which outputs light at a predetermined wavelength, and a laser control circuit which supplies a predetermined timing pulse for generation of relaxation oscillation in a laser drive current supplied to the laser drive circuit, the laser control circuit supplying a laser drive current higher than a threshold value which is supplied from the laser drive circuit to the laser element to enable laser light to be output from the laser element, the laser control circuit setting the laser drive current to a level lower than the threshold value on the basis of the timing pulse.