A swing device includes a seat member, a pair of swing arms that are connected to the seat member, and a driving unit including an axle that is secured to one of the swing arms, a swingable member that is secured to the axle, a pair of studs that project from the swingable member, and a driving element including a driving rod that has a bent middle segment and two opposite bent end segments, each of which extends from the middle segment in a first direction away from the middle segment, passes over a respective one of the studs, and then turns in a second direction toward the respective one of the studs, and each of which has a free end portion that is disposed adjacent to and that is engageable with the respective one of the studs.