A high-density region-containing sheet having a high-density region and a low-density region, a sheet member produced by joining the high-density region of the high-density region-containing sheet to an elastic member, and a disposable diaper using the sheet member as its chassis are provided. A sheet in a soft state by imparting preheat is pressed between a pair of opposed shaping rolls and having a toothed region and rotatable. Thus, a high-density region-containing sheet where high-density regions and low-density regions are formed is produced. Such two high-density region-containing sheets are joined through an extended elastic member to form a projection/recess pattern. In such a way, a high-density region-containing sheet can be produced. A sheet member in which at least one of two sheets is a high-density region-containing sheet, the high-density regions are joined through an extended elastic member, and a projection/recess pattern can be formed when the elastic member is contracted is produced.
