A filling apparatus comprising: a hydrogen gas supply source, a filling hose with a filling nozzle designed to be connected to a vehicle-side tank of a vehicle, a hydrogen supply pipe connected on its upstream side to the hydrogen gas supply source via an accumulator and on its downstream side to the filling hose, and a control unit, wherein said control unit has a function of transmitting a control signal of a pressure of hydrogen gas required by the hydrogen filling apparatus and supplied by the hydrogen gas supply source and the accumulator via a control signal line to the hydrogen gas supply source, and wherein the control unit has a function of setting to boo st the required pressure of hydrogen gas supplied by the hydroge n gas supply source and the accumulator until an initi al pressure measurement of an initial pressure is completed, wher ein the initial pressure is a discharge pressure in a state where hydrogen is present in the filling hose immediately before filli ng, and is measured with a discharge pressure gauge of the filling apparatus, and wherein the pressure corresponds to a pressure in the vehicle-side tank, characterized in that the control unit is linked with the filling nozzle via a measurement signal line in such a way that pressure and temperature information of a pressure inside the vehicle-side tank and a temperature inside the vehicle-side tank is transmitted to the control unit, wherein said control unit has a function of determining whether or not a communication filling is established, wherein the communication filling is established when the pressure and temperature information is transmitted to the control unit, wherein, when the communication filling is established, said control unit has a function of setting the required pressure of hydrogen gas supplied by the hydrogen gas supply source higher than the internal pressure, wherein, when the communication filling is not established, said control unit has a function of setting the required pressure of hydrogen gas supplied by the hydrogen gas supply source to a pressure of 30 to 60% of a maximum value. a hydrogen gas supply source, a filling hose with a filling nozzle designed to be connected to a vehicle-side tank of a vehicle, a hydrogen supply pipe connected on its upstream side to the hydrogen gas supply source via an accumulator and on its downstream side to the filling hose, and a control unit, wherein said control unit has a function of transmitting a control signal of a pressure of hydrogen gas required by the hydrogen filling apparatus and supplied by the hydrogen gas supply source and the accumulator via a control signal line to the hydrogen gas supply source, and wherein the control unit has a function of setting to boo st the required pressure of hydrogen gas supplied by the hydroge n gas supply source and the accumulator until an initi al pressure measurement of an initial pressure is completed, wher ein the initial pressure is a discharge pressure in a state where hydrogen is present in the filling hose immediately before filli ng, and is measured with a discharge pressure gauge of the filling apparatus, and wherein the pressure corresponds to a pressure in the vehicle-side tank, characterized in that the control unit is linked with the filling nozzle via a measurement signal line in such a way that pressure and temperature information of a pressure inside the vehicle-side tank and a temperature inside the vehicle-side tank is transmitted to the control unit, wherein said control unit has a function of determining whether or not a communication filling is established, wherein the communication filling is established when the pressure and temperature information is transmitted to the control unit, wherein, when the communication filling is established, said control unit has a function of setting the required pressure of hydrogen gas supplied by the hydrogen gas supply source higher than the internal pressure, wherein, when the communication filling is not established, said control unit has a function of setting the required pressure of hydrogen gas supplied by the hydrogen gas supply source to a pressure of 30 to 60% of a maximum value.