PURPOSE: To remove ink and Japanese ink from paper-making raw material with extremely high efficiency.

CONSTITUTION: A tank A having an oblong box form is partitioned at the middle part with a gate plate 1 inclined toward the outlet side. A stirring layer A1 is formed between the gate plate 1 and an inlet port 2 and a static flow layer A2 is formed between the gate plate 1 and the outlet layer 3 for the paper-making raw material. The paper-making raw material in the stirring layer A1 is ejected to the side of the inlet port 2 with an ejection pump 4 capable of introducing air and placed in the stirring layer A1.