PURPOSE: To obtain a uniform coil winding by forming a resonant circuit consisting of a wound coil, obtaining a winding error from a resonant frequency and by compensating a coil winding data through numerical control.
CONSTITUTION: When an independent coil 13 is formed by winding a wire material to a stick 7, an elastic contact 16 is placed in contact with a contact 17 of stick and a resonant frequency f1 of resonant circuit formed in combination with a detector 12 is thereby output. The frequency f1 is compared with the reference frequency fo of the coil 13 being stored in a memory 14 and a deviation indicated by a digitalized voltage value is sent to a small size operation circuit 11' as a compensating data. The operation circuit 11' selects a winding method to be compensated in a coil to be formed next in accordance with a winding data stored with the winding pitch and controls a number of rotations and amount of movement of nozzle 5 on the numerical control basis, completing the next coil. As explained above, a winding error is fed back to an automatic winding apparatus and therefore a uniform and accurate coil winding can be realized.