A disposable diaper using elastic sheet materials so that a contact surface pressure may be locally enhanced and thereby the diaper may be prevented from being noticeably displaced on the wearer's body during used thereof is provided. Of first and second waist regions at least the first waist region is contractible. The first waist region includes waist auxiliary elastic sheets extending in a direction of a transverse axis between opposite side edges of the first waist region and leg auxiliary elastic sheets extending along front peripheral edges of leg-openings. The waist auxiliary elastic sheets and the leg auxiliary elastic sheets overlap one another in areas of the opposite side edges of the first waist region adjacent to the leg-openings respectively. With the diaper put on the wearer's body, these areas come in contact with upper lateral regions of the wearer's iliac bones inclusive of the vicinity thereof.