A clean assembling module device that achieves cleanliness of a work area where assembling, processing, transportation, etc. of a work item are performed and that can be downsized. The invention also includes a production system, an industrial robot, and a pollution spread prevention system that are formed with the device. A clean assembling module device is provided with clean air generation means on the top of the device and is formed so as to have a work area, a clean air retaining/exhausting area and a mechanism section area, in that order from the top side of the device. The outer periphery of the work area is shielded by a clean area shielding wall. Fluid resistance between the work area and the clean air retaining/exhausting area is controlled by a partition wall having small holes. Air came through the work area and the clean air retaining/exhausting area is exhausted by an air exhausting fan to outside the device. The work area is positively pressurized, and the mechanism section area is negatively pressurized relative to the work area. Pressure in the clean air retaining/exhausting area is adjusted by the small holes of the partition wall and by rotation speed of the air exhausting fan so as to be intermediate between the pressure in the work area and the pressure in the mechanism section area.