UNIT SWING ENGINE

There is provided a unit swing engine swingably supported by a vehicle body frame. The unit swing engine includes: a cylinder tilted forward horizontally or nearly horizontally; a cylinder head connected to a front surface of the cylinder; a crankcase connected to a rear surface of the cylinder; a first ignition plug disposed on a top surface of the cylinder head; and a second ignition plug disposed on a side surface of the cylinder head. The vehicle body frame includes a frame member extending in an upper-lower direction in front of the crankcase. The second ignition plug is disposed inside the frame member and in front of the frame member.