A paper dispenser contains a receiving compartment for a dispenser roll, a transport path leading from above into the receiving compartment, a hold position for a spare roll being defined in the transport path by a blocking device, and a transfer device for the paper of the spare roll once the paper of the dispenser roll is used up. The width of the receiving compartment is smaller than the diameter of the spare roll, and a sensor element for the diameter of the spare roll releases the blocking device not before the diameter of the spare roll has been reduced to the width of the receiving compartment.