A wavelength conversion apparatus capable of stably providing high output harmonic laser light is provided. The wavelength conversion apparatus comprises an end pump fiber laser 3 containing a laser activating substance, and including a reflecting surface at one end thereof and a fiber grating in the vicinity of the reflecting surface; an excitation laser light source 1 for outputting excitation laser light; an excitation laser light introduction section 4 for introducing the excitation laser light from the excitation laser light source to the fiber laser; a wavelength conversion element 5 for converting a fundamental wave generated by the fiber laser to a harmonic; and a rear reflecting surface 6 located outside the fiber laser and forming a laser cavity together with the fiber grating.