A warp determination device for a corrugated cardboard sheet manufacturing device is provided with: displacement value measurement method for measuring displacement values of a plurality of corrugated cardboard sheet pieces on the downstream side of a slitter scorer and on the upstream side of a sheet stacking unit; and warp status determination means for dividing a measurement range of the displacement value measurement method according to a width dimension of the plurality of corrugated cardboard sheet pieces, allocating the divided measurement ranges to each of the plurality of corrugated cardboard sheet pieces, and determining a warped status of the corrugated cardboard sheet pieces for each of the plurality of corrugated cardboard sheet pieces on the basis of measurement values from the displacement value measurement method in the allocated measurement ranges.