An adjusting device adjusts a reticle unit of a telescopic sight and has a rotatable setting cap and a transmission unit for converting the turning movement of the setting cap into an adjusting movement of the reticle. The turning range of the setting cap is two revolutions and arranged on the adjusting device there are two sets of scale values assigned to at least one line scale. A first set of scale values indicate adjustment values that belong to the first revolution of the setting cap and a second set of scale values indicate adjustment values that belong to the second revolution. An index ring that bears the scale values and can be turned with the setting cap or a diaphragm ring that partially covers at least one index ring is adjustable in height during the transition from the first revolution to the second revolution of the setting cap.