An exercise mechanism for a training machine is disclosed wherein the training machine includes a machine base and at least one handle which is operable to swing. The exercise mechanism includes at least one support and a rotary disk, wherein the at least one support is pivotally connected to the machine base and has a first end and a second end which are respectively on two sides of a portion pivoted to the machine base; the at least one support moves to generate a relative up and down displacement between the first end and the second end when the handle swings; the first end is pivotally connected to the machine base via a linkage assembly; the rotary disk would be driven to rotate when the second end moves whereby the exercise mechanism is capable of operating the training machine.