A hydraulic cam shaft adjuster has a driven outer body comprising at least one hydraulic chamber, and an inner body disposed on the inside of the outer body (4), which can be firmly attached to the camshaft and has at least one pivoting wing extending into the hydraulic chamber in the radial direction, thus partitioning the hydraulic chamber into a first working chamber and a second working chamber. The inner body has at least one oil inlet and oil outlet conduit extending from a jacket interior to a jacket exterior of the inner body up to one of the two working chambers. The inner body is assembled using at least one first element and one second element, wherein the two elements each have at least one geometry at front sides facing each other, forming the oil inlet and oil outlet conduit of the inner part together with the other element.