To provide a viscosity liquid supply method which can supply a viscosity liquid by scooping up it without making it remain even if the viscosity liquid is accumulated in a viscosity liquid accumulation vessel having a diameter-contracted part smaller in diameter than that of the other point.

In the viscosity liquid supply device 10, there is used a ventilation structure 40 larger in outside diameter than the inside diameter of a portion which is the largest in cross section in an internal space of the viscosity liquid accumulation vessel B, and having continuous air bubbles. When scooping up the viscosity liquid from the viscosity liquid accumulation vessel B, firstly a lead-out pipe 30 is inserted into the liquid in a preparation process, and the ventilation structure 40 and a plate member 50 are arranged on the viscosity liquid. Furthermore, the viscosity liquid accumulation vessel B is arranged in a pressure vessel 20. After that, by forming the inside of the pressure vessel 20 into a pressurized atmosphere in a lead-out process, the viscosity liquid adhered on an inner wall face of the viscosity liquid accumulation vessel B is scraped by the ventilation structure 40, and the viscosity liquid is led out to the outside via the lead-out pipe 30.