To provide a gas feeder which prevents an error in the gas filling amount into a tank, and does not apply a large load on a gas supplying passage while gas filling is not carried out.

The gas feeder fills a tank 3a with high pressure gas from a dispenser 1 having a gas cut off valve 1e, a flowmeter 1c, and a control device 1h until reaching predetermined pressure, after uniting a coupling 2 at a tip end of a filling hose 4b to a tank 3a. In case that starting of the gas supply to the tank 3a is instructed after the coupling 2 is united to the tank 3a, gas filling to the tank 3a is not immediately started. The control device 1h opens only the cut off valve 1e first to raise gas pressure in a gas supplying passage 4 including the filling hose 4b to a fixed value, and then starts flow rate measurement and opens a main valve 2b of the coupling 2 to start gas filling to the tank 3a. The gas flow rate measurement and gas filling to the tank 3a is started after the gas pressure in the gas supplying passage 4 becomes the specified value.