To provide wafer aligning method and apparatus which can align wafers with a simple construction by reducing moving parts.

A controller 12 obtains a rectangular coordinate system having the rotational center of a table as an origin from polar coordinate values of peripheral positions of a wafer 3 from positions of the rectangular coordinate system. After that, a plurality of center positions of the wafer 3 are obtained from the positions of the rectangular coordinate system. The controller 12 compares the plurality of center positions and recognizes two coincided center positions as a true center position of the wafer 3. The radius (rw) of the wafer 3 is compared with the radius (rn) of each of the detected 36 peripheral positions, thereby detecting the peripheral positions of two different radii. The peripheral positions of the two different radii correspond to a linearly notched part as an orientation flat 9. The inclination (θ) of the orientation flat 9 is obtained from the peripheral positions, the wafer is turned by an amount of the inclination (θ) of the orientation flat, and the position of the orientation flat 9 is accurately aligned.