In a rotor of a rotating electric machine, a slot includes a winding insertion portion and a widened portion. A width dimension of the widened portion is larger than a width dimension of the winding insertion portion. A pair of step portions are formed on both sides of an end portion of the winding insertion portion on the widened portion side. A wedge member is spaced from and opposed to the pair of step portions. An insulation includes: an insulation main body arranged between a rotor winding and a damper bar; and an extended portion, which is arranged in at least a part of a space between the wedge member and the pair of step portions, and is configured to suppress movement of the damper bar in a circumferential direction of a rotor core.