A screen printing apparatus for printing paste on a printed pattern of a print target constituted of a substrate or a plurality of aligned substrates includes a mask having a plurality of opening patterns different in size from one another. The screen printing apparatus images the substrate or one of the aligned substrates constituting the print target, and calculates a level of deformation by expansion and contraction of the print target, based on a result of the imaging. The screen printing apparatus then selects an opening pattern from among the opening patterns, based on the calculated level of deformation by expansion and contraction of the print target, brings the print target into contact with the mask to superimpose the selected opening pattern on the printed pattern, and deposits the paste on the printed pattern.