In a wet friction material, to be able to obtain a more significant drag torque reduction effect certainly by making it easy to discharge a lubricating oil which is supplied from an inner peripheral side of a core metal into an outer peripheral side and by preventing a stirred torque from increasing by generating oil retained at an outer periphery, and moreover to be able to obtain a more significant drag torque reduction effect even in case of a specification that there is no lubricating oil supply from the inner peripheral side.In a segment-type friction material 1, it promotes ATF to discharge into outside a diameter and enhances a cavitation by giving R processing to an inner periphery and an outer periphery of segment pieces 3A, 3B so as to shorten an oil groove 4A, and yet it can restrain a stirred torque resulting from forming oil retained by ATF caused by that a space in the outer peripheral side is secured by giving R processing to the outer periphery of segment pieces 3A, 3B.