A magnet type fan clutch apparatus is formed of an electromagnetic clutch mounted on one driving shaft, and a magnet coupling operatively connected to the electromagnetic clutch. The magnetic coupling includes a permanent magnet rotary body to which a fan is fixed, and a disc having a conductor or a hysteresis member opposed to the permanent magnet rotary body with a narrow clearance left therebetween; and formed so that the permanent magnet rotary body and disc are rotated together or relatively owing to an attraction working between the permanent magnet and conductor. The magnetic coupling is formed so as to be ON/OFF controlled by the electromagnetic clutch, and a seal structure is provided between the disc and permanent magnet rotary body.