A light source device includes a light source for emitting a laser beam, a power supply drive circuit for pulse-driving the laser beam, a wavelength conversion element for converting a wavelength of a laser beam into a predetermined wavelength, a photodetector for detecting an intensity of the laser beam emitted from the wavelength conversion element, and a control section that controls a drive condition of the laser beam emitted from the wavelength conversion element based on the intensity detected by the photodetector, wherein the control section includes an optimization setting section that, in response to the intensity of the photodetector in a present pulse drive condition being outside a predetermined range, controls a drive condition of the laser beam to extract an optimum pulse drive condition, and sets the extracted optimum pulse drive condition to the drive condition of the laser beam instead of the present pulse drive condition, and the optimization setting section, in extracting the optimum drive condition, restores the present pulse drive condition in a predetermined period of time after replacing the present pulse drive condition with a predetermined pulse drive condition for extracting the optimum pulse drive condition.