To provide a film forming device capable of easily preventing foreign matters from being mixed into a coating film on a substrate to be treated.

This film forming device is provided with a target 5 to be sputtered under the reduced pressure, a power source 4 applying voltage to this target 5 and a substrate placing stand 9 on which the substrate 8 to be treated is placed, a passing sheet 7 having an opening 7a through which sputtered particles 6 advancing toward the substrate 8 from the target 5 are interposed between the target 5 and the substrate placing stand 9, the passing sheet 7 is provided with a heat generating means 15, and this heat generating means 15 is controlled by a control means 17 for controlling the heating state of the passing sheet 7 based on the electric power feeding state of the power source 4 to the target 5. Moreover, it is possible that the passing sheet 7 is provided with a temp. detecting means transmitting the heating state of the passing sheet 7 to the control means 17.