A wavelength conversion apparatus capable of keeping high wavelength conversion efficiency for a longer time than ever before is provided. A wavelength conversion apparatus includes: a wavelength conversion section including a nonlinear optical crystal, and performing wavelength conversion of incident laser light by allowing the incident laser light to pass through the nonlinear optical crystal; and a relative position control section, when wavelength conversion is performed by the wavelength conversion section, relatively displacing the incident position of the incident laser light in an incident plane into which the incident laser light enters of the nonlinear optical crystal in a direction including a projection direction component of a +C axis to the incident plane in the nonlinear optical crystal or a direction orthogonal to the projection direction component.