PURPOSE: To simply and easily insert a cleaning sponge for performing cleaning in a pipe into a pump cylinder.

CONSTITUTION: An inserting adapter 15 is inserted into an opening part 10 of a pump cylinder 1 communicating with the inside of a hopper 7. When a stop part 18 of the inserting adapter 15 is brought into contact with an edge of the opening part 10 and stopped, the inside of the pump cylinder 1 is partitioned into the inside of a cylinder part 16 of the inserting adapter 15 and a passage 19 formed of a flat plate-shaped partitioning wall 17 of the inserting adapter 15 and the pump cylinder 1. In this condition, when a cleaning sponge 14 is inserted into the cylinder part 16, since washing water 20 in the pump cylinder 1, passing through the passage 19, is discharged from the pump cylinder 1, the cleaning sponge 14 can be smoothly inserted.