A first locking mechanism is configured to block rotating the first and second holders by locking an operation component or by locking the first and second holders when the cap is not mounted on one of the first and second holders, and is configured to unlock rotating the first and second holders by being engaged with the cap when the cap is mounted on one of the first and second holders and when the cap is arranged to face upwardly towards a upper side. A second locking mechanism is configured to block rotating the first and second holders by locking the operation component or by locking the first and second holders when the cap is mounted on one of the first and second holders and when the cap is arranged to face downwardly to a lower side opposite to the upper side.