Abstract: A tree climbing device which includes a rope clamp that can be locked to a rope having a tree trunk-encircling loop, and which is connected to a user harness so that a climber can be suspended from the tree trunk by the device during the climbing process. The clamp comprises rope-gripping member with adjacent opposing ends spaced from each other, that together with link plates pivotally attached to the members on either side thereof define a space through which the rope is passed. The end of each of the members opposite the space is pivotally attached to one end of different support legs, the other end of the legs being attached to a support bar. Spring means are provided which urge the support bar from one of the link plates, reducing the space, and locking the rope therein. When pressure is applied opposite to such urging, the space is increased, unlocking the device so that the rope can be moved through the clamp for rope adjustment purposes required to facilitate the climbing process.