A hydraulic machine has a gear wheel (2) with outwardly extending teeth and a gear ring (4) with inwardly extending teeth formed by rollers each of which is supported in a pocket (8) in the gear ring, and pressurized spaces are formed between the gear wheel and the inwardly extending teeth. To keep the wear of the machine small, each pocket (8) has at least two different radii (R1, R2, Rn) whereby a radius (R2, Rn) at a smaller displacement from the edge (12) of the pocket is larger than a radius (R1) at a larger displacement from the same edge (12) of the pocket (8).