A climbing machine includes two sets of two inclined parallel rails disposed on a base and frame assembly; two pedals slidably disposed on the sets of the rails respectively; a transmitting device including an axle disposed under front portions of the sets of the rails and oriented in a direction perpendicular to a virtual plane defined by the sets of the rails, a first sprocket disposed around the axle, a second sprocket disposed adjacent to a center of a bottom of a rear end of the base and frame assembly, and a disc shaped damping member with the first sprocket mounted in its center; and a belt meshing with the first and second sprockets, the belt 28 being parallel to the sets of the rails. The pedals are secured to the belt and disposed at two sides of the first and second sprockets respectively.