Disclosed herein is a human powered rail bike. The rail bike includes a chassis having a predetermined shape. Rail wheels comprising a pair of front wheels and rear wheels, roll along two rails of the track which are arranged side by side. A plurality of seats is mounted to the chassis. A one-way clutch capable of changing direction limits the rotating direction of an axle to one direction, that is, a forward direction or a backward direction. A plurality of crank pedals is rotatably mounted to the chassis, and is connected to the one-way clutch capable of changing direction via a chain. A direction conversion lever functions to convert the rotating direction of the one-way clutch. Further, a pair of brake units is provided to reduce the speed of the rail bike or stop the rail bike.