It has been shown that the heating rate in annealing white iron, whose compositions are of malleable iron, influences its graphitizing phenomena remarkably; the rapid heating such as by dipping in molten lead causes the refinement of the graphite nodules by subsequent annealing, which was reported previously, the moderate rate of heating as the heating to the graphitizing temperature in about 10 hrs. results in the coarsening of the particles, and the slow heating as in the case of heating to the graphitizing temperature in about 40 hrs. causes to increase the graphite nodule number.As mentioned above, the size of the graphite particles by annealing becomes larger as the heating rate increases, and then smaller by the extremely rapid heating, which is probably explained by the relations among the stability of cementite, its growth and the heat-treatment. It is clear that the large number of graphite particles may be caused by the graphitization of cementite without its grawth.The number of nodules is affected by chemical compositions and freezing conditions. The difference of nodule number between the rapidly heated samples by dipping in lead bath and the very slowly heated samples is smaller at the cast state in sand mould than at the cast state in metal mould. Iron containing 0.9∼1.1%Si showed also smaller difference than that containing about 1.3%Si. The difference of nodule number between the rapidly heated samples by dipping in lead bath and the samples heated in about 10 hrs. to the annealing temperature is smaller in samples cast in sand mould than in samples cast in metal mould. Samples with a few percentage of Al or Mn show almost no difference in the industrial rate of heating.