A surgical microscope has an illuminating arrangement for illuminating light in an operating region to be examined with the surgical microscope. The arrangement contains a high-power light source which includes an intensity adjusting device. The device makes possible an adjustment of the intensity of the illuminating light, which is guided to the object region, between a maximum value and a minimum value. The microscope has a control unit for the illuminating arrangement which includes an operator-controlled module via which the illuminating arrangement can be activated and controlled. For adjusting the intensity of the illuminating light guided to the operating region, the control unit coacts with the adjustable filter unit. A signal generator outputs a warning signal when an intensity of the illuminating light is adjusted via the operator-controlled module which exceeds the safety limit value stored in a memory.