A device including: a main folding mechanism for folding a diaper body in two at the crotch portion by rotating first and second main pads having first and second holding surfaces respectively and a sub-folding mechanism for folding the flap by rotating a side pad having a sub-holding surface for holding the flap with respect to the first main pad wherein: a cut-out is formed at a position corresponding to the attachment portion of the second main pad wherein the cut-out does not allow the attachment portion to be held by the second main pad but instead expose the attachment portion with the first and second holding surfaces being closed
