tanks 41 a to 41 c the dispersion liquid in the discharge chambers 42 a to 42 c does not drop from the discharge holes and therefore the dispersion liquid 48 a to 48 c in the buffer tanks 41 a to 41 c is not transferred to the discharge chambers 42 a to 42 c each discharge chamber 42 a 42 c has cells corresponding to the discharge holes and each cell has a piezoelectric element when a voltage is applied to the piezoelectric element the piezoelectric element expands and contracts by the piezoelectric effect whereby the dispersion liquid in each cell is pressurized and discharged from the discharge hole of the cell toward the surface of the substrate 7 when the dispersion liquid in the discharge chamber 42 a to 42 c is discharged the dispersion liquid is drawn from the buffer tank 41 a to 41 c in order to supply to the discharge chamber 42 a to 42 c with the amount of the dispersion liquid 48 a to 48 c discharged if the liquid level of the dispersion liquid in the buffer tanks 41 a to 41 c drops a pressurized gas is introduced into the buffer tanks 41 a to 41 c from the gas feeding system 57 or the dispersion liquid is supplied from the first circulation tank 31 l or the second circulation tank 31 r as described later so that the pressure of the space in the buffer tanks 41 a to 41 c.