An obstruct of this invention is to downsize a chamber, consequently a film forming system, to improve a film thickness distribution and to improve throughput of film forming by increasing the amount of the vaporized liquid precursor. The film forming system 1 is to form a film by vaporizing a liquid precursor and then depositing the vaporized liquid precursor on a substrate W, and comprises a chamber 2 inside of which the substrate W is held and multiple injection valves 3 that are arranged at different positions in the chamber 2 and that directly inject the identical liquid precursor in the chamber 2, vaporize the identical liquid precursor by flash boiling and then supply the vaporized liquid precursor.