Abstract: A rotary magnetic sensor for generating electrical signals corresponding to rotation of a shaft, which comprises a rotary disk or drum made of non-magnetic material, a magnet installed in the center of said disk or drum, a magnetic film applied on the disk or drum and connected to said magnet, a magnetic-film pattern formed in said magnetic film in which magnetic flux distribution is varied in the rotating direction of said rotary disk or drum, and a magnetic sensitive means disposed in the proximity of said magnetic-film pattern whereby electrical signals are generated in accordance with the rotation of said disk or drum.