An apparatus and a method for dual mode depth measurement are provided. The apparatus is used for measuring a depth information of a specular surface in a depth from defocus (DFD) mode or measuring a depth information of a textured surface in a depth from focus (DFF) mode. The apparatus includes a light source, a controller, a processor, a lighting optical system, an imaging optical system, a beam splitter and a camera. The controller is for switching between the depth from defocus mode and the depth from focus mode. The lighting optical system is used to focus a light from the light source on an object surface in the depth from defocus mode, and the lighting optical system is used to illuminate the object surface with a uniform irradiance in the depth from focus mode.