A method for producing a flexible sheet includes a stretching step in which a base sheet (10) is fed from between a pair of first drive rollers (42, 43) into the bite of a pair of intermeshing corrugated rollers (2, 3) and stretched in the machine direction between the corrugated rollers (2, 3). In the method, the peripheral velocity V1 of the first drive rollers (42, 43) and the peripheral velocity V2 of the corrugated rollers (2, 3) have a relation of V1>V2.