Abstract: A rope climber for hanging on a steel cable, a rope or a long pole suspended in the air and operable to enable a person's body to be lifted up or lowered down the cable or rope and to stop at any position on the cable or rope. The rope climber includes a pair of grooved wheels having the outer circumferences in close contact and capable of rotating in opposite directions, one or both of the grooved wheels having at the middle of the outer circumferences eccentric grooves, the grooved wheels defining at the close contact point of the outer circumferences a hole through which the cable or rope passes. By rotation of the grooved wheels the hole can be varied in size, whereby the rope climber is able to slide up and down the cable or rope when the hole is large in size and will hold the cable or rope tightly and stay at any fixed place on the cable or rope when the hole is small.