A pump for pumping one or more media comprises a housing (1) having an actuator chamber (2) and at least one pump chamber (4). The pump chamber (4) is provided with an inlet port and an outlet port. The pump chamber (4) is delimited by a displacement member (5) which is movable to and fro between a first position and a second position. The pump further comprises a movable actuator body (3), accommodated in the actuator chamber (2) and consisting of a magnetizable or magnetic material, for driving the displacement member (5). The pump also comprises magnetic drive means (8a, 8b) for creating a magnetic field in order to move the actuator body (3). The actuator body (3) is freely movable relative to the displacement member (5) so that the displacement member (5) can be moved, by means of an impact motion of the actuator body (3), from the first to the second position.