PURPOSE: To shorten the time for adjusting an equipment while exposure is interrupted during the operation of the equipment.

CONSTITUTION: In an exposure equipment, an electron beam 12 emitted from an electron gun 11 is shaped into a rectangular section by a beam shaping plate 13, and the image thereof is formed on a mask plate 17 by a first lens 14. In the readjustment of the equipment after the operation is started, the image size of the beam shaping plate 13 on the mask plate 17 is measured and compared with a similar image size which is previously measured when a power supply of the equipment is turned on and rise adjustment is finished. The change amount of comparison is calculated. The operating current value of the first lens 14 is changed stepwise, and the image size is measured each time. A map of the change amounts from the image size when the rise adjustment is finished is obtained. The operating current value of the first lens 14 is changed to the value at which the change amount of the image size become minimum.