A blade body for a rotary machine, the blade body being intended to be disposed in plural number on a rotary body at an equal interval in the circumferential direction of the rotary body to define a flow channel through interspaces between adjacent blade bodies, the blade body comprising: a main body which has a dorsal face and a ventral face; and a trailing edge portion (26;36) which connects the dorsal face to the ventral face with a continuous curved face (25;35), wherein the trailing edge portion (26;36) is the portion of the dorsal and ventral faces (2,3) of the main body that extends further downstream from points on the dorsal and ventral faces (2,3) that are determined as connection points of a fictive circular arc which connects the dorsal and ventral faces (2,3) and that define the location of the throat which is the part at which the flow channel between adjacent blade bodies is narrowest, wherein the curved face (25;35) of the trailing edge portion (26;36) is gradually decreased in curvature radius from one of the dorsal face and the ventral face toward a rear end portion (27;37) of the main body which is positioned most downstream in a direction in which a fluid flows through the flow channel defined between adjacent blade bodies, wherein the curved face (25;35) of the trailing edge portion (26;36) is decreased to the greatest extent in curvature radius at the rear end portion (27;37), wherein the curved face (25;35) of the trailing edge portion (26;36) is gradually increased in curvature radius from the rear end portion (27;37) toward the other of the dorsal face and the ventral face, and wherein the trailing edge portion (26;36) is such that the change of the curvature radius of a part (25a;35a) of the curved face (25;35) positioned at the dorsal face side in the vicinity of the rear end portion (27;37) is different from the change of the curvature radius of a part (25b;35b) of the curved face (25;35) positioned at the ventral face side in the vicinity of the rear end portion (27;37). a main body which has a dorsal face and a ventral face; and a trailing edge portion (26;36) which connects the dorsal face to the ventral face with a continuous curved face (25;35), wherein the trailing edge portion (26;36) is the portion of the dorsal and ventral faces (2,3) of the main body that extends further downstream from points on the dorsal and ventral faces (2,3) that are determined as connection points of a fictive circular arc which connects the dorsal and ventral faces (2,3) and that define the location of the throat which is the part at which the flow channel between adjacent blade bodies is narrowest, wherein the curved face (25;35) of the trailing edge portion (26;36) is gradually decreased in curvature radius from one of the dorsal face and the ventral face toward a rear end portion (27;37) of the main body which is positioned most downstream in a direction in which a fluid flows through the flow channel defined between adjacent blade bodies, wherein the curved face (25;35) of the trailing edge portion (26;36) is decreased to the greatest extent in curvature radius at the rear end portion (27;37), wherein the curved face (25;35) of the trailing edge portion (26;36) is gradually increased in curvature radius from the rear end portion (27;37) toward the other of the dorsal face and the ventral face, and wherein the trailing edge portion (26;36) is such that the change of the curvature radius of a part (25a;35a) of the curved face (25;35) positioned at the dorsal face side in the vicinity of the rear end portion (27;37) is different from the change of the curvature radius of a part (25b;35b) of the curved face (25;35) positioned at the ventral face side in the vicinity of the rear end portion (27;37).