A method of manufacturing disposable diapers having a structure in which theposition of an absorption core of a disposable diaper is not displaced from thecenter between a pair of leg elastic members. The method has a sheet member manufacturingprocess (P1) in which elastic members are joined in a stretched state to a sheetcontinuously supplied in a machine direction (MD) to form belly side and backside sheet members (20, 30), a joining process (P2) in which absorptive panels(4) are joined to the belly side and back side members at constant intervals, theabsorptive panels (4) each having a pair of crotch elastic members (42) attachedin a stretched state along opposite long sides of an oblong shape of the absorptivepanel (4) and also each having absorptive cores (5) joined to the absorptive panel(4) so as to be symmetrical about an imaginary center line bisecting the distancebetween the pair of crotch elastic members (42), and a cutting process (P3) forcutting the belly side and back side sheets to which the absorptive panels (4)are joined.
