A rotary actuator includes a motor, an output shaft, and a speed reducer. The motor includes a motor shaft rotating about an axial direction. The output shaft is disposed in parallel with the motor shaft. The speed reducer reduces a rotational speed of the motor and transmits rotation of the motor at a reduced rotational speed to the output shaft. The speed reducer includes a parallel-shaft type reducer that has a drive gear on the motor shaft and a driven gear on the output shaft. One side and the other side in the axial direction are defined as a first side and a second side, respectively. The motor is located on the first side of the speed reducer in the axial direction. The driven gear includes a teeth portion having a gear end surface on the first side of the teeth portion. The motor includes a stator having a stator end surface on the second side of the stator. The gear end surface is located on the first side of the stator end surface in the axial direction.