A disposable diaper (1) comprises a covering article main body (2), and a pair of fastening members (40) which are joined at both end parts of the covering article main body in the width direction. The covering article main body is folded back toward the interior in the width direction with a pair of reference folds (FL1) being base points, said pair of reference folds (FL1) being located further in the interior in the width direction than join parts (44) at which the covering article main body and the fastening members are joined. The reference folds are formed only in the covering article main body without being formed in the fastening members.