A silicon film forming apparatus includes a deposition chamber (10), a silicon sputter target (2) arranged in the chamber, a hydrogen gas supply circuit (102 or 102′) supplying a hydrogen gas into the chamber, and a high-frequency power applying device (antenna 1, 1′, power source PW and others) generating inductively coupled plasma by applying high-frequency power to the gas supplied into the deposition chamber (10). Chemical sputtering is effected on the target (2) by the plasma to form a silicon film on a substrate S. A silane gas may be used. A silane gas supply circuit (101) may be provided with a gas reservoir unit (GR). The silicon film can be formed inexpensively and fast at a relatively low temperature.