Abstract: Wastepaper is treated by a ink-removing process in which an aqueous wastepaper pulp slurry is introduced into a treating vessel, air is blown into the wastepaper pulp slurry preferably through a number of air-blowing orifices formed on a peripheral surface of at least one horizontal cylinder located in the bottom portion of the vessel to absorb ink particles floating in the wastepaper pulp slurry by air bubbles ejected from the orifices and rising toward the wastepaper pulp slurry surface. The resultant ink-absorbed froth is then removed. In this process, air is blown in an amount satisfying the relationship (I)G/L.gtoreq.5.0 (I)wherein L is the volume (m.sup.3) of the wastepaper pulp slurry in the treating vessel and G is the total volume (Nm.sup.3) of the air bubbles blown into the vessel, to promote the contact of the air bubbles with the ink particles in the wastepaper pulp slurry.