The additive manufacturing apparatus includes: a height measurement unit outputting a measurement result of height at a measurement position of a build object formed on a workpiece during additive processing; and a control unit controlling a processing condition in performing new stacking at the measurement position in accordance with the measurement result. The height measurement unit includes a measurement illumination system irradiating the measurement position with measurement illumination light, an optical axis of the measurement illumination light is inclined with respect to an optical axis of a light receiving optical system, and the measurement illumination light is continuously emitted in an angular range of at least ±90 degrees with reference to a direction opposite a direction of supply of the processing material with the optical axis of the light receiving optical system as a center of a rotational angle range.