A novel adjustable screed bar holder used to support screed bars used in concrete finish work. The holder moves along a supporting device such as a stake, pin, or post. A lever on the holder is coupled to a cam wheel such that movement of the lever will disengage the cam wheel from the stake. When the cam wheel is in the disengaged position the holder is free to move along the stake until the lever is released and the cam wheel secures against the stake. Typically the holder will be used to hold a piece of lumber, pipe, rebar, or tubing parallel to the forms used in concrete placement. A screed may then be run over the concrete while it rides on the screed bar supported by the adjustable holder.