Abstract: The engageable structure of the operation rod in the pump includes a valve member having an outer sleeve as an outer valve, an inner sleeve as an inner valve installing in the outer sleeve rotatably and a pushing operation body with a sliding part installed in the inner sleeve and with a driven operation rod; a drive source; and a driving operation rod moves horizontally due to guiding by a supporting member arid force of the drive source, and a catching part of the valve member engages with a connection-supporting device which is attached to the driving operation rod when the driven operation rod of the valve member and driving operation rod of the drive source are connected.