An extraction bag (1A-1G) comprising: a bag main body formed of a water permeable filter sheet; thin plate-like member provided on an outer surface of the bag main body; and an extraction material filled in the bag main body, wherein the bag main body has a first surface and a second surface opposed to each other, and an upper side corresponding to edges of the first and second surfaces; when the bag main body is developed so that the first 10 surface is located under the upper side and the second surface is located above the upper side, the thin plate-like member includes a first member on the first surface of the bag main body, and a second member on the second surface of the bag main body, and the thin plate-like member includes a central bonded portion bonded to the first surface of the bag main body in a central portion of the first member, a pair of elongated regions sandwiching the central bonded portion from its left and right sides, and a vertical folding line (Lv1') along which the pair of elongated regions can be pulled out from sides closer to lateral sides of the bag main body so as to be opposed to each other, characterized in that he first member and the second member are continuous with each other via a first horizontal folding line extending along the upper side and in that the pair of elongated regions are provided astride the first member and the second member. the bag main body has a first surface and a second surface opposed to each other, and an upper side corresponding to edges of the first and second surfaces; when the bag main body is developed so that the first 10 surface is located under the upper side and the second surface is located above the upper side, the thin plate-like member includes a first member on the first surface of the bag main body, and a second member on the second surface of the bag main body, and the thin plate-like member includes a central bonded portion bonded to the first surface of the bag main body in a central portion of the first member, a pair of elongated regions sandwiching the central bonded portion from its left and right sides, and a vertical folding line (Lv1') along which the pair of elongated regions can be pulled out from sides closer to lateral sides of the bag main body so as to be opposed to each other, characterized in that he first member and the second member are continuous with each other via a first horizontal folding line extending along the upper side and in that the pair of elongated regions are provided astride the first member and the second member. a central bonded portion bonded to the first surface of the bag main body in a central portion of the first member, a pair of elongated regions sandwiching the central bonded portion from its left and right sides, and a vertical folding line (Lv1') along which the pair of elongated regions can be pulled out from sides closer to lateral sides of the bag main body so as to be opposed to each other, characterized in that he first member and the second member are continuous with each other via a first horizontal folding line extending along the upper side and in that the pair of elongated regions are provided astride the first member and the second member.