To provide a method of sufficiently demagnetizing a steel cord, and to provide an automobile tire having a steel cord demagnetized by the method.

An adjoining one magnet 6 among the magnets 6 arranged in a width direction of a steel cord group 4 has N-pole on the steel cord group 4 side, and the other magnet 6 has S-pole on the steel cord group 4 side. Looped magnetic line m in almost semi-circular arc or semi-oval arc is generated from the magnet 6 toward the passing zone of the steel cord group 4, thereby forming a static magnetic field. When the steel cord group 4 passes through the static magnetic field, the magnetic line penetrates the steel cord group 4 in the width direction to demagnetize each steel cord 2 of the steel cord group 4.