PROBLEM TO BE SOLVED: To provide a tape type diaper which hardly applies a burden on a body in putting the diaper on an underweight baby in a posture with an abdominal side on a lower side and both legs bent.SOLUTION: A tape type diaper (1) for an underweight baby that has a maximum length of 330 mm or less in a longitudinal direction in a spread and expanded state includes: a side flap (20) equipped with a pair of front side extending parts (20A) and a pair of back side extending parts (20B)； a fastening tape (40) fixed on the pair of the front side extending parts； and a target region (45). In putting on a wearer lying on a belly with both legs bent, one side in the longitudinal direction is applied to an abdominal side, the front side extending parts are wrapped along a waist from the abdominal side to a back side, and the pair of the fastening tapes can be engaged in the target region on the back side. A maximum value of a curvature in a curve part in a base, to the outside in a width direction, of the front side extending part is larger than a maximum value of a curvature in a curve part in a base, to the outside in the width direction, of the back side extending part.SELECTED DRAWING: Figure 1【課題】腹部を下側にして両脚を屈曲させた姿勢を取っている低体重児に着用させる際に、身体に負担をかけにくいテープ型おむつを提供する。【解決手段】展開且つ伸長した状態での長手方向の最大長さが３３０ｍｍ以下の低体重児用のテープ型おむつ（１）であって、一対の前側延出部（２０Ａ）及び一対の後側延出部（２０Ｂ）を備えたサイドフラップ（２０）と、一対の前側延出部に固定されたファスニングテープ（４０）と、ターゲット領域（４５）と、を有し、腹を下向きにして両脚を屈曲させた姿勢で寝ている着用者に着用させる際には、腹側に長手方向の一方側をあてがい、前側延出部を胴回りに沿って腹側から背側に回しこみ、一対のファスニングテープを背側のターゲット領域で係合可能であり、幅方向の外側に向う前側延出部の根元の曲線部分の曲率の最大値が、幅方向の外側に向う後側延出部の根元の曲線部分の曲率の最大値よりも大きい。【選択図】図１
