An electric actuator (100) includes: a screw shaft (111) mounted on the one end (200T1) side of a pull bar (200) and having a helical first groove (121) in the outer peripheral surface thereof; a rotor (113) having a hollow portion (113I) in which the screw shaft (111) is disposed and also having a helical second groove (122) which is formed in a part of the inner peripheral surface of the hollow portion (113I) and which corresponds to the first groove (121), the hollow portion (113I) allowing the other end (200T2) side of the pull bar (200) to protrude therefrom; balls (123) disposed between the first groove (121) and the second groove (122); an element (112) mounted to the rotor (113) and circulating the balls (123); a stator (110) for moving the pull bar (200) in the longitudinal direction thereof by rotating the rotor (113); and a rotation prevention member (107) engaging with a part of the pull bar (200) and preventing the rotation of the pull bar (200).
