A laser light-source apparatus comprising: a first light source configured to output pulse light based on gain switching; a fiber amplifier configured to amplify the pulse light output from the first light source and producing ASE during amplification; a solid state amplifier configured to amplify the pulse light output from the fiber amplifier; a nonlinear optical element configured to perform wavelength conversion on the pulse light output from the solid state amplifier and output the resultant pulse light; a second light source that is provided on an upstream side of the solid state amplifier and is configured to output laser light that is combined with the pulse light output from the first light source; an optical switching element that is disposed between the fiber amplifier and the solid state amplifier, and is configured to permit or stop propagation of light from the fiber amplifier to the solid state amplifier and is configured as a filter in the time domain to remove the ASE; and a control unit configured to achieve in an output permitted state in which the nonlinear optical element outputs the resultant pulse light, an output stopped state in which the nonlinear optical element stops outputting the resultant pulse light by stopping propagation of the pulse light from the first light source to the solid state amplifier, with power of excitation light to the solid state amplifier maintained, and to perform control in such a manner that the second light source oscillates in the output stopped state; wherein the control unit is configured to control the optical switching element in such a manner that the propagation of the pulse light from the fiber amplifier to the solid state amplifier is permitted in an output period of the pulse light from the first light source and that the propagation of the pulse light from the fiber amplifier to the solid state amplifier is stopped in a period other than the output period of the pulse light from the first light source in the output permitted state, and to perform control in such a manner that the second light source stops oscillating in the output permitted state, and wherein the control unit is configured to control the optical switching element in such a manner that the propagation of the pulse light from the fiber amplifier to the solid state amplifier is stopped in the output period of the pulse light from the first light source and that the propagation of the pulse light from the fiber amplifier to the solid state amplifier is permitted in a period other than the output period of the pulse light from the first light source in the output stopped state, and to perform control in such a manner that the second light source oscillates at least in the period other than the output period of the pulse light from the first light source in the output stopped state. a first light source configured to output pulse light based on gain switching; a fiber amplifier configured to amplify the pulse light output from the first light source and producing ASE during amplification; a solid state amplifier configured to amplify the pulse light output from the fiber amplifier; a nonlinear optical element configured to perform wavelength conversion on the pulse light output from the solid state amplifier and output the resultant pulse light; a second light source that is provided on an upstream side of the solid state amplifier and is configured to output laser light that is combined with the pulse light output from the first light source; an optical switching element that is disposed between the fiber amplifier and the solid state amplifier, and is configured to permit or stop propagation of light from the fiber amplifier to the solid state amplifier and is configured as a filter in the time domain to remove the ASE; and a control unit configured to achieve in an output permitted state in which the nonlinear optical element outputs the resultant pulse light, an output stopped state in which the nonlinear optical element stops outputting the resultant pulse light by stopping propagation of the pulse light from the first light source to the solid state amplifier, with power of excitation light to the solid state amplifier maintained, and to perform control in such a manner that the second light source oscillates in the output stopped state; wherein the control unit is configured to control the optical switching element in such a manner that the propagation of the pulse light from the fiber amplifier to the solid state amplifier is permitted in an output period of the pulse light from the first light source and that the propagation of the pulse light from the fiber amplifier to the solid state amplifier is stopped in a period other than the output period of the pulse light from the first light source in the output permitted state, and to perform control in such a manner that the second light source stops oscillating in the output permitted state, and wherein the control unit is configured to control the optical switching element in such a manner that the propagation of the pulse light from the fiber amplifier to the solid state amplifier is stopped in the output period of the pulse light from the first light source and that the propagation of the pulse light from the fiber amplifier to the solid state amplifier is permitted in a period other than the output period of the pulse light from the first light source in the output stopped state, and to perform control in such a manner that the second light source oscillates at least in the period other than the output period of the pulse light from the first light source in the output stopped state.