<p>The allowable temperature range satisfying the phase matching conditions of a wavelength conversion element is widened. The light wavelength conversion light source comprises a semiconductor laser diode element (1) provided with an antireflection film (3), a lens (4) arranged opposite to the semiconductor laser diode element (1), an optical fiber (5) having a core arranged with Bragg diffraction grating (6), and a wavelength conversion element (8) consisting of a nonlinear optical crystal receiving light from the semiconductor laser diode element (1). The semiconductor laser diode element (1) oscillates in coherent collapse mode.</p>
