Disclosed are a beam scanner and a surface measurement apparatus. The beam scanner includes a spinning mirror having top and bottom reflective surfaces and a plurality of side reflective surfaces between the top and bottom reflective surfaces, and rotating about a rotary shaft penetrating the top and bottom reflective surfaces to scan beams, falling onto the side reflective surface, in one direction, a first light source emitting first beams to the side reflective surface, a second light source emitting second beams to at least one of the top and bottom reflective surfaces, and a detector receiving beams reflected by the spinning mirror, among the second beams. The beam scanner and the surface measurement apparatus can achieve high-speed, high resolution surface measurement since errors caused by the movement of the spinning mirror for beam scanning are minimized.