Screen printing apparatus, electronic component mounting system and screen printing method

A screen printing apparatus includes a substrate positioning part that upwardly and downwardly moves a substrate with the substrate clamped by a clamp member to thereby bring the substrate into contact with a mask stretched in a frame body and fixed in a predetermined height position from an underside of the mask and position the substrate in a predetermined height position, a mask suction part that is provided in the clamp member and sucks the mask in contact with the substrate, and a screen printing part that prints paste on the substrate through a pattern hole formed in the mask by sliding a squeegee on the mask to which the paste is supplied. The mask is pressed up by a predetermined amount through the substrate with the mask sucked by the mask suction part when the substrate is upwardly moved by the substrate positioning part.