Abstract: In a distributor assembly having an ignition coil therein, for use with an internal combustion engine, the positional relationship between the ignition coil and a magnetic sensitive detector, which detects a proper ignition timing, is selected so that the leakage flux from the ignition coil does not cause the magnetic sensitive detector to malfunction. According to one arrangement the magnetic sensitive direction of the detector is arranged perpendicular to the leakage flux from the ignition coil. According to the other arrangement the magnetic sensitive direction of the detector is arranged to intersect a radial line from the axis of the main magnetic flux of the ignition coil at an angle other than 90 degrees so that the flux variation in the detector is expedited by the appearance and disappearance of the leakage flux.