The present application discloses a wavelength conversion device. The wavelength conversion device includes a light source for generating excitation light, a laser medium for generating fundamental light from the excitation light, a resonator mirror for forming a resonator for the fundamental light in cooperation with the laser medium, and a wavelength convertor for converting wavelength from the fundamental light into harmonic light. The wavelength convertor includes a first end surface inclined by an angle θ from a surface orthogonal to an optical axis of the resonator and a second end surface parallel to the first end surface.