Disposable diaper

A disposable diaper having:

• a front waistline region;
• a back waistline region;
• and a crotch region which is positioned between the front waistline region and the back waistline region, the disposable diaper having:
• a product longitudinal direction which is oriented from the front waistline region to the back waistline region;
• and a product widthwise direction which is orthogonal to the product longitudinal direction, the disposable diaper comprising:
• an absorber running across the crotch region and extending at least one of the front waistline region and the back waistline region;
• a side flap which run across the front waistline region, the crotch region, and the back waistline region, which is disposed at an outside of the product widthwise direction than the absorber;
• and
• a pair of fastening tapes each extending from the back waistline region to the outside of the product widthwise direction of the respective one of the side flaps and securely attaching to the front waistline region;
• wherein the side flaps each has:
• an leg opening unit which is concave toward a center in the product widthwise direction of the absorber;
• and a leg stretching unit which is disposed inside of product widthwise direction than the leg opening unit, which stretches in the product longitudinal direction,
• wherein the leg opening unit has:
• a backside leg opening unit which is positioned a backward than the center of the product longitudinal direction of the leg opening unit;
• and a foreside leg opening unit which is positioned at a front side than the center of the product longitudinal direction of the leg opening unit,
• wherein an area between the backside leg opening unit and a straight line which passes through a center in the product widthwise direction and which is in parallel to the product longitudinal direction is larger than an area between the foreside leg opening unit and a straight line which passes the center in the product widthwise direction and which extends in the product longitudinal direction,
• wherein a buttocks part stretching unit which is disposed so as to run across the crotch region and the back waistline region and which stretches in the product longitudinal direction is disposed at the outside of the product widthwise direction than the leg stretching unit, and
• wherein a front end of the buttocks part stretching unit is positioned more backward than a center of the product longitudinal direction of the leg opening unit.