There is provided an inexpensive stage which is equipped with an alignment function and is capable of easily performing high-accuracy alignment especially in a θ direction even in case an object to be processed is large in weight. The stage equipped with an alignment function has a stage main body for holding a substrate while leaving a processing surface thereof open to access. The stage is provided with: a suction means capable of sucking that surface of the substrate which lies opposite to the processing surface; a gas supply means for supplying a gas to such a region of the substrate as is other than a portion sucked by the suction means; and a drive means to give a rotating force to the suction means so that the substrate can be rotated on the same plane by causing the suction means to serve as the center of rotation.