To obtain a controller for controlling the rolling angle of orientation of a flying object by detecting the rolling angle of orientation of a missile accurately throughout the flight thereof without relying on an inertial unit or the like.

First and third antennas 2, 15 having identical planes of polarization symmetrical to the axis of machine are arranged in the rear of a flying object. The quadrant where a rolling angle of orientation is present can be determined by comparing the intensity of receiving signal between the first and third antennas 2, 15 having identical planes of polarization and the rolling angle of orientation can be controlled by detecting it accurately throughout the flight of the object.