A wind power rotor with measuring device (3) for measuring rotor deflection. A measuring cavity (20), which has a transmitter/receiver (31/32) at one end and a reflector device (33) at the other end, extends in a longitudinal direction of the rotor. The transmitter/receiver (31/32) is accommodated in a housing (50), which is fastened to an intermediate plate (10) with three-point mounting (12, 13, 14).