Nine photographs taken on March 25, 1986 at Mount John Observatory show that the nucleus of Comet Halley split into two widely separated nuclei. The projected distance of separation on the plane of the sky is about 5×103 km. The principal nucleus and the seconddary nucleus exhibit their own comas. The prominent jet ejected from the companion curves up to a height of several thousand kilometers and the secondary nucleus must fade out of sight within only a few days. In combination with the results of photoelectric observations taken by Chen Peisheng et al. (1987), it seems that this splitting event coincides with an optical outburst.Some photographs have been digitized and their image enhancements have been carried out.