A laser light-source apparatus includes a control unit configured to perform control in such a manner that a seed light source is driven in a pulse oscillation mode of oscillating pulse light based on gain switching in an output permitted state where output of pulse light from the apparatus is permitted, and is driven in a continuous oscillation mode of oscillating continuous light in an output stopped state in which the output of the pulse light from the apparatus is stopped, with power of excitation light for a solid state amplifier maintained, and adjusts power of laser light input to the solid state amplifier from the seed light source in the continuous oscillation mode in such a manner that the solid state amplifier outputs light with substantially same average power in the output stopped state and in the output permitted state.