To regenerate a compressed air supply device of a commercial vehicle, a first compressed air circuit is supplied with compressed air until reaches a predetermined target pressure value; then a second compressed air circuit is supplied. Between these steps, the method: (1) regenerates an air dryer when the pressure in the first compressed air circuit has reached the target pressure value, and when a moisture value of the air dryer exceeds a predetermined target moisture value; (2) terminates the regeneration when the pressure has dropped to a predetermined limit pressure value or the moisture value of the air dryer has reached or dropped below the target moisture value; (3) supplies the first compressed air circuit until it has reached the predetermined target pressure value; and (4) repeats the preceding intermediate steps when the moisture value is greater than the target moisture value.