An apparatus for manufacturing an absorbent body includes: a sheet supplying mechanism for supplying a sheet from a sheet roll a crusher for crushing the sheet into a fibrous matter by scraping a reeling-out tip end of the reeled out sheet and a fiber stacking device for forming the absorbent body in a predetermined shape by laminating the fibrous matter to be sent out from the crusher. When switching a supply of the sheet to the crusher from one to another sheet supplying mechanism, at least two sheet supplying mechanisms supply the sheet to the crusher over a predetermined period including a period in which the one sheet supplying mechanism decreases a sheet reeling-out speed, in correspondence with the period in which the one sheet supplying mechanism decreases the sheet reeling-out speed, the other sheet supplying mechanism increases a sheet reeling-out speed.