PURPOSE: To simultaneously attain the alignment to both faces of a printed circuit board by aligning in advance the upper and lower mask films being in a horizontal attitude, and thereafter, placing the printed circuit board between them, and displacing a supporting body for holding the mask films through an optical device, a displacement device, etc.

CONSTITUTION: In an attitude in which a pair of upper and lower mask films 22 are provided adjacently, the respective television cameras 36 in an optical device 35 are placed at prescribed positions, and a reference mark for an alignment provided on a part of each mask film 22 is photographed. This photographing signal in sent to a control value setting device 42, the deviation of each reference mark is calculated, and a supporting body 24 is displaced in the direction where this dislocation becomes zero, by which the alignment is executed. Thereafter, both mask films 22 are separated, and between them, a board supporting frame 15 for holding a printed circuit board 14 is placed, and the alignment of three of the upper and lower mask films 22 and the printed board 14 is executed simultaneously and exactly through an optical device 35, the control value setting device 42, and a displacement device 29, and thereafter, double face printing by an exposure light source 5 is executed.