A method for quickly applying and spreading adhesive between substrates without leaving air bubbles. The method includes holding two substrates apart from each other with adhesive sides facing, a second substrate being positioned above a first substrate. The second substrate is suspended in a manner so as to cause a portion to warp towards the first substrate. After a liquid filler is applied between the two substrates, rollers are lowered onto the second substrate and moved so as to disperse the liquid filler between the first and second substrates. In accordance with the rolling of the rollers, end portions of the second substrate are lowered towards the first substrate.