To provide a confocal displacement sensor that can prevent deterioration in measurement accuracy due to a spherical aberration of an optical member. The confocal displacement sensor includes a light source for light projection configured to generate light having a plurality of wavelengths, a pinhole configured to emit detection light by allowing the light emitted from the light source for light projection to pass, an optical member configured to generate an axial chromatic aberration in the detection light emitted via the pinhole and converge the detection light toward the measurement object, a measurement control section configured to calculate displacement of the measurement object on the basis of, in the detection light irradiated on the measurement object via the optical member, detection light passed through the pinhole by being reflected while focusing on the measurement object, and a head housing configured to house the pinhole and the optical member. The optical member includes a first diffraction lens configured to diffract the detection light and a first refraction lens configured to refract the detection light. The first diffraction lens is disposed with a non-diffraction surface exposed from the head housing.