PURPOSE: To provide a filtration vessel for filtrating coffee and a filtration device using the vessel, not bulky for storage and housing purposes, allowing an easy operation and ensuring a low price, together with a method for using the vessel.

CONSTITUTION: An approximately trapezoidal bag made of a base material of nonwoven fabric, paper or a synthetic resin film, is formed out of a bag 10 with an opening on the side corresponding to the bottom of a trapezoid, and a hard plate 2 mounted along the edge of the opening 11 of the bag 10, with a fold 9 formed thereon so as to allow easy bending. Furthermore, at least one hole of a diameter approximately between 2 and 15mm is opened through the bottom 5 of the bag 10.