A wavelength conversion laser 100 is provided with a solid-state laser having a cavity, and a wavelength converting element 6 arranged within the cavity. The solid-state laser includes two or more types of laser crystals 4 and 5 and oscillates solid-state laser light of multiple wavelengths. The wavelength converting element 6 converts the solid-state laser light of multiple wavelengths into light of second harmonic waves and sum-frequency wave of multiple wavelengths and simultaneously generates the second harmonic waves and sum-frequency wave of multiple wavelengths. The wavelength conversion laser 100 outputs converted wavelength light having a broad spectral width and low coherency, thereby enabling it to carry out highly efficient and stable high-output oscillation.