An upright bike includes a main frame including a front portion and a rear portion. A rail structure is connected to the rear portion of the main frame. An X-shaped frame is slidably mounted to the rail structure and pivotally connected to the front portion of the main frame. A slide end is formed on the X-shaped frame and slidably mounted onto the rail structure. A stepping structure is mounted on a lower section of the first trestle of the X-shaped frame. A seat is secured on a top of the first trestle of the X-shaped frame. A handlebar is transversally secured on the X-shaped frame. A restitute element has two opposite ends respectively secured on the first trestle and the second trestle of the X-shaped frame for providing restitution force to the X-shaped frame when the handlebar is upwardly pulled.