Here is disclosed a waist band for diaper to connect the front and rear waists at each side. In contrast with the pressure-sensitive adhesive tape of prior art which necessarily forms an overlapping portion of said front and rear waists at each side of the diaper when the latter is put on the user, this waist band has not only a function to adjust a circumferential dimension of the waist but also the fastening function of the conventional adhesive tape. The waist band disclosed herein has a relatively large length including an area of low rigidity (or high flexibility) serving for said adjusting function and another area of high rigidity serving for said fastening function. Furthermore, this waist band is made of basic material consisting of nonwoven fabric having high flexibility and plastic film which is at least partially melted into said nonwoven fabric integrally therewith so that said area serving for fastening function may have a desired high rigidity.