PURPOSE: To securely execute forced filtration by charging material and hot water from the upper part opening of an extraction room to rotate a valve element, pouring hot water from the upper opening and pressing the valve element to a valve sheet after that to execute forced-filtration.

CONSTITUTION: A filter receiver 3 blocks the bottom face opening 2 of a brewer unit 1 to push down the valve element 6 against the energizing force of a compression spring 21 to open the upper part opening 5. Then, material and hot water are charged to the extraction room from the upper part opening 5. Air 10 is blown from a feeding port 9 in the state so as to stir the mixed liquid 11 of material and hot water. Next, a motor 27 is driven to rotate a shaft 19 to rotate the valve element 6 and a stirring body 28. Then, a little amt. of hot water is poured from the upper part opening 5. With the rotation of the valve element 6, material stuck to the valve element 6 is overshot by centrifugal force, splashed to the extraction room 4 and removed. Then, the driving of the motor 27 is finished and the pushing-down of the valve element 6 is released to block the upper part opening 5 with the valve element 6 to hermetically close the extraction room 4.