PURPOSE: To correct warpage efficiently according to a degree of the warpage by providing a roll capable of varying a roll crown and a bending roll, or providing a crown roll and a bending roll.

CONSTITUTION: The warpage correction device A is constituted of a roll, which can vary a roll crown with compressed air or the like as a medium, and a bending roll. This device can cope with the degree of the warpage of a printed wiring board 4 by varying the roll crown of the roll 1. According to the device, the printed wiring board 4 is applied with warps in both x and y directions, and the warps are corrected. Or the warpage correction device A is constituted of a crown roll 3 and a bending roll 2. This device can cope with the warpage of the printed wiring board 4 by changing the space between both rolls 3 and 2, or by changing the pressing force of the bending roll 2. With this device warpage of the printed wiring board 4 in x and y directions is also corrected.