In a camshaft adjusting device comprising an adjusting mechanism for adjusting the phase positions of first and second camshafts with respect to a crankshaft driving the camshaft adjusting device, the adjusting mechanism includes an adjustment input and first and second outputs connected to the first and second camshafts respectively, with first and second transmission ratios, respectively, for changing the phase angles between the drive input and the first and second outputs respectively, at different rates when the adjustment input is actuated.