Many investigators have been working on the self inductance of a coil near a conductor. The author calculated magnetic field and self inductance of a circular loop near a conductor and tried to obtain data applying the results to a spiral coil and a solenoid coil etc. In this paper it was analyzed assuming that the conductor was a perfect conductor. Satisfying the condition as much as possible, self inductance was measured. The experimental values are considerably in accord with the theoretical values.