An exercise device includes a frame, two first swing arms, two second swing arms, two pedals, a resistance device, two cranks, two link rods, two supporting mechanisms, two rock rods, and two adjusting devices. Each first swing arm couples with the frame and has a lower end coupling with a first end of one second swing arm. Each second swing arm has a second end coupling with one pedal. Each crank has a first end coupling with the resistance device and a second end coupling with a first end of one link rod. Each link rod has a second end coupling with one second swing arm. Each rock rod has a first end pivotally coupling with a fulcrum of one supporting mechanism and a second end coupling with one second swing arm. Each adjusting device adjusts the distance between the second end of one rock rod and one fulcrum.