A golf swing plane training device is disclosed that helps the user develop a correct swing plane as well as exercise the muscle groups most effective in imparting maximum power to a golf ball. The device is portable and comprises a rotating swing plane guide, one end pivotably connected to a club shaft, for controlling the swing arc of the club shaft when swung by the user to ingrain the feel of swinging on plane. The other end of the rotating swing plane guide is connected to a rotation control assembly mounted on a vertically adjustable support frame. A resistance source is connected to the hub of the rotation control assembly.