An electromagnetic rotary driving device including a rotor of a permanent magnet arranged in a hole formed in a bored stator core block of a stator core, made from magnetic material. The air gap formed between the bored block of the stator core and the rotor in the direction parallel with the magnetic path in the stator core is relatively long, while the air gap formed between the bored block of the stator core and the rotor in the direction perpendicular to the magnetic path in the stator core is relatively short. In this device, the angle of rotation of the rotor is continuously changed by the current flowing through the coil of the stator without requiring a spring for return motion.