In an absorbent sheet manufacturing apparatus, a storage part stores speed determining information including relationships between conveying speed of a first sheet member and rotational speed of a supply cylinder and corresponding respectively to target particle densities. A control part determines the rotational speed of the supply cylinder on the basis of a target particle density, the conveying speed and the speed determining information. Even if various changes are made to the conveying speed of the first sheet member, the amount of particles supplied can be accurately controlled such that the density of particles on the first sheet member matches the target particle density. Even if various changes are made to the target particle density, the amount of particles supplied can be accurately controlled in consideration of the conveying speed such that the density of particles matches the target particle density.