Bumper reinforcement and bumper device for vehicle

A bumper reinforcement (16, 40) having end portions in the width direction of a vehicle, includes a main wall (21, 41) extending in a first direction perpendicular to the width direction, first and second walls (22, 23/42, 43) protruding from the main wall (21, 41) in the first direction to extend toward an interior side of the vehicle in a longitudinal direction of the vehicle, flanges (24, 44) protruding from respective ends of the first and second walls (22, 23/42, 43) along the first direction, the main wall (21, 41), the first and second walls (22, 23/42, 43), and the flanges (24, 44) being integrally formed with one another, and gradually narrowing portions (22b, 23b/42b, 43b) formed, in the width direction, at end portions of each of the first and second walls (22, 23/42, 43), wherein respective protruding lengths of the first and second walls (22, 23/42, 43) in the longitudinal direction gradually decrease from an intermediate portion of the bumper reinforcement (16, 40) to the end portions of the bumper reinforcement (16, 40) in the width direction to form the gradually narrowing portions (22b, 23b/42b, 43b).