An outer surface of a cam on a camshaft extending along a camshaft axis is honed by continuously rotating the camshaft about its axis while holding a grinding stone adjacent the cam with a surface of the stone directed radially inward at the cam surface. Movement of the grinding stone is restricted to displacement in two directions, one direction extending substantially radially of the camshaft axis and the other direction extending generally perpendicular to the one direction. The grinding stone is urged in the one direction extending radially of the axis against the stone to press the cam surface radially inward against the cam surface for contact of the stone surface along a line with the cam surface so that the stone moves in a radial direction as the camshaft rotates. The stone surface is continuously reciprocated in the other direction generally parallel to a plane perpendicular to the radial direction so as to continuously move the contact line between the cam and stone surfaces.