Patent attributes
A measurement apparatus having a measurement light source for emitting measurement light, a projection unit on which reflected light formed when the measurement light is reflected from the mirror plane is projected as a projected light spot, an image pickup unit for picking up an image of the projection unit on which the reflected light is projected as the projected light spot, a control unit for controlling an inclination of the mirror plane and a measurement unit for measuring a quantity of movement of the projected light spot, which moves according to a change of the inclination of the mirror plane, on the basis of the image of the projection unit. This enables the measurement of a deflection characteristic of a mirror system having the mirror plane variable to arrange the inclination within a short period of time and with high accuracy.