To appropriately fill a liquid chemical storage part with a liquid chemical without making a user perform troublesome operations.

By driving a sealing member 8 in the direction of widening an internal space 9 of a liquid chemical storage part 6, the inside of the liquid chemical storage part 6 is turned to a negative pressure, and the liquid chemical storage part 6 is filled with the liquid chemical from a liquid chemical container 31 connected to the liquid chemical storage part 6. Thereafter, by driving the sealing member 8 in the direction of narrowing the internal space 9 of the liquid chemical storage part 6, a pressure is applied to the liquid chemical, with which the liquid chemical storage part 6 is filled, and air inside the liquid chemical storage part 6 is discharged through an opening 6B of the liquid chemical storage part 6. Thus, without making a user perform the operation of filling with the liquid chemical using an injector for instance or discharging the air separately, the liquid chemical storage part 6 is filled with the liquid chemical and the air inside the liquid chemical storage part 6 is discharged. Thus, the liquid chemical storage part 6 is appropriately filled with the liquid chemical without making the user perform the troublesome operations.