sent out if the pump is brought into such a state liquid in the discharge passage 22 flows into the pump chamber 16 from downwardly through the reflow passage 23 and a portion of gas in the pump chamber 16 is discharged into the discharge passage 22 disposed in the upper portion of the pump chamber 16 this action is repeatedly carried out to discharge all gas in the pump chamber 16 and thereafter only liquid can be discharged into the discharge passage 22 from the pump chamber 16 the discharge passage 22 is formed substantially in parallel to and above the pump chamber 16 and the reflow passage 23 which brings the discharge passage 22 and the pump chamber 16 into communication with each other is provided at the predetermined position with this configuration even if the pump 6 is mounted such that the discharge port 21 is oriented in a direction other than the upward direction the liquid in the discharge passage 22 reflows into the pump chamber 16 through the reflow passage 23 all gas in the pump chamber 16 is discharged into the discharge passage 22 as described above and then fluid can be discharged from the discharge port 21 and as a result liquid can be discharged from the pump chamber 16 according to the second embodiment as described above it is possible to.