PURPOSE: To correct the error of pitch by setting the irradiation angle of exposing and illuminating light by widening or narrowing it, detecting a pattern provided between a mask and a substrate so that the error of the pitch may be calculated and controlling a distance between the mask and the substrate based on the calculated result.

CONSTITUTION: A substrate chuck 6 is moved by using a substrate chuck lifting and lowering mechanism 13 so that the distance between the mask 1 and the substrate 4 may be set at a standard value. Next, the pitch of a pair of alignment marks 2 and 5 of the mask 1 and the substrate 4 are detected by the use of a detecting optical system 7 and a detecting element 8. Then, the error amount of the pitch is calculated by an arithmetic device 9. When the error amount can be corrected, the distance between the mask 1 and the substrate 4 is controlled to the obtained distance by moving the substrate chuck 6 up and down by the mechanism 13 after calculating the error of the pitch and the tilt θ of the exposing and illuminating light 11 by a specified expression by using the arithmetic device 9. Then, exposure is performed by using the exposing and illuminating light 11, the error of the pitch is corrected and a mask pattern is transferred to the substrate 4.