A disposable pull-on undergarment includes each of front and rear waist-encircling regions having a first elasticized zone and a second elasticized zone extending in a waist-encircling direction. Tensile stress of the first elasticized zone is greater than that of the second elasticized zone. The undergarment thus constituted can reduce an incidence of intense pressure locally exerted on a waist of a wearer of the undergarment and avoid an occasion whereby an excrement-absorbing function of a core is hindered.