The utility model discloses a spun yarn broken wire detection apparatus of twin coil electromagnetic induction difference formula, including two permanent magnets, coil, ring rail, rings and steel wire winding, two coaxial settings of permanent magnet are on the ring rail, and the distance is adjustable between two permanent magnets, and the winding of same root coil is on two permanent magnets, and the rings is fixed to be set up on the ring rail, and steel wire winding latch closure is on the rings, and the axle center of rings is located the perpendicular bisector of two permanent magnet lines, and the mid point of permanent magnet line and the perpendicular distance in rings axle center are the half the 3-5mm in addition of rings bulge internal diameter. The utility model discloses it is with low costs, install the small installation of being convenient for, the interference killing feature is strong, and to the on -the -spot common condition strong adaptability of various spinning such as the yarn that wafts, it is high to detect the precision to the broken string, and response speed is fast, and it is wide to be suitable for frequency range, the effectual function that realizes the fast monitor broken string, the reclosing productivity gain immediately of being convenient for.