A liquid pump comprising: a suction port for sucking a liquid; a pump chamber communicating with the suction port , the pump chamber being defined by a wall, a part of which is a vibrating wall part vibratable to dynamically change a volume of the pump chamber ; a discharge-side communicating passage extending from the pump chamber ; a discharge-side tank part communicating with the pump chamber through the discharge-side communicating passage to store the liquid delivered from the pump chamber ; a discharge-side check valve disposed between the discharge-side tank part and the pump chamber to allow passage of fluid therethrough from the pump chamber toward the discharge-side tank part but prevent passage of fluid therethrough from the discharge-side tank part toward the pump chamber ; and a discharge port discharging the liquid from the discharge-side tank part ; wherein the liquid is sucked in from the suction port and discharged from the discharge port in response to vibration of the vibrating wall part ; the discharge-side tank part having a first inner wall surface and a second inner wall surface facing each other in a horizontal direction in an installed position of the liquid pump , the first inner wall surface being formed with the discharge port , the second inner wall surface being formed with an open end of the discharge-side communicating passage , the discharge-side tank part being configured such that an air pool (A2) is formed in a space in the discharge-side tank part above the open end of the discharge-side communicating passage and the discharge port ; the liquid pump characterized by : a partition projecting from the second inner wall surface toward the first inner wall surface in the discharge-side tank part at least at a position above the open end of the discharge-side communicating passage so as to cover the open end as seen from the air pool side. a suction port for sucking a liquid; a pump chamber communicating with the suction port , the pump chamber being defined by a wall, a part of which is a vibrating wall part vibratable to dynamically change a volume of the pump chamber ; a discharge-side communicating passage extending from the pump chamber ; a discharge-side tank part communicating with the pump chamber through the discharge-side communicating passage to store the liquid delivered from the pump chamber ; a discharge-side check valve disposed between the discharge-side tank part and the pump chamber to allow passage of fluid therethrough from the pump chamber toward the discharge-side tank part but prevent passage of fluid therethrough from the discharge-side tank part toward the pump chamber ; and a discharge port discharging the liquid from the discharge-side tank part ; wherein the liquid is sucked in from the suction port and discharged from the discharge port in response to vibration of the vibrating wall part ; the discharge-side tank part having a first inner wall surface and a second inner wall surface facing each other in a horizontal direction in an installed position of the liquid pump , the first inner wall surface being formed with the discharge port , the second inner wall surface being formed with an open end of the discharge-side communicating passage , the discharge-side tank part being configured such that an air pool (A2) is formed in a space in the discharge-side tank part above the open end of the discharge-side communicating passage and the discharge port ; the liquid pump characterized by : a partition projecting from the second inner wall surface toward the first inner wall surface in the discharge-side tank part at least at a position above the open end of the discharge-side communicating passage so as to cover the open end as seen from the air pool side. <EOS>