To provide a micro fluid device capable of transporting a fluid by an easy method, without requiring piping for pump mechanism drive, or wire connection for a diaphragm, in a micro fluid device having an extremely small diaphragm type pump mechanism.

This micro fluid device has the pump mechanism comprising flow passages 6, 6', non return valves 8, 9 disposed in the middle of the flow passage, and a pump chamber 5. The pump chamber or the fluid passage is formed by a cavity (cavity A) made by laminating and adhering a thin film member (member C) facing the chipped portion and becoming a diaphragm 17 to a chipped portion of a member (member A). A ferromagnetic material 14 is fixed to be mounted on the diaphragm, or a cavity (cavity F) is disposed at an opposite side to the member (A) of the diaphragm, and the cavity (cavity F) is filled with the ferromagnetic material to be mounted therewith. The diaphragm is deformed by ferromagnetic action to vary volume of the pump chamber and opens and closes the non-return valves, thereby transporting the fluid in the flow passages.