An engagement device includes: a clutch unit including annular input and output elements disposed so as to face each other in an axial direction, plate-shaped engagement pieces provided in the input element or the output element, and an annular selector plate disposed between the input and output elements to switch a posture of the engagement pieces and switched between an engagement state and a release state; and an actuator operating the selector plate and control the engagement state and the release state of the clutch unit. Further, the actuator includes an actuator main body generating a force for operating the selector plate, and the actuator main body is disposed radially inwards beyond the clutch unit.