Pattern forming apparatus and pattern forming method

The supply of a negative pressure to an opening P(+1) adjacent to an opening P(0) is stopped by switching a suction valve connected to the opening P(+1) from an open state to a closed state while keeping a positive pressure valve connected thereto closed. Then, near the opening P(+1), a force for holding a blanket becomes gradually weaker against a pressure force in a pressurized space. Associated with that, an air component in the pressurized space flows into a space between a portion of the blanket vertically above the opening P(+1) and an upper surface, whereby the blanket portion is lifted from the upper surface and brought into contact with the lower surface of a printing plate. In this way, a contact area is slowly and stably widened while a sudden change of a pressure in the pressurized space SP5 is suppressed.