PURPOSE: To provide a replacing device of bottles by which bottles can be easily replaced even in a narrow space and the deviation of residual liquid is little.

CONSTITUTION: A bottle-replacing device is provided with the first cylinder 1 attached to the inside of bottle so that one of front ends is positioned at the opening 40a of the bottle 40, a joint 30 detachably fitted to the bottle 40, the second cylinder 2 detachably fitted to the front end 1a of the first cylinder 1 by the joint 30. Since the first cylinder 1 is separated from the second cylinder 2 by raising the joint 3, the stroke becomes shorter when the joint 30 is raised.