A breast pump includes a body including a hood attachment portion, a bottle attachment portion, and an inner passage extending between the hood attachment portion and the bottle attachment portion; a diaphragm configured to generate negative pressure in the inner passage; a handle manually operated to move back and forth; and a link mechanism configured to support the handle in a manner movable back and forth relative to the body. The handle is configured to change pressure of the inner passage from a normal state to a negative state by displacing the diaphragm in a lifting direction. The link mechanism is configured to apply an operation force to the handle that becomes maximal during handle movement when the handle is moved in an operation direction that changes the pressure from the normal state to the negative state.