Crystalline powders of Si and M (transition metal) in the composition ratio Si:M = 2:1 were mechanically alloyed by a laboratory ball mill in an inert atmosphere. The progress of the mechanical alloying was identified by X-ray diffraction. The amorphization reaction between Si and M proceeded according to a second-order reaction. The sequence of the rate of amorphization reaction for the SI-M system was Mn > Ti > V > Ni > Co. The sequence of the rate was correlated to the volume ratio (V-M/V-Si) of the SI-M system except for Si-Ni system. The crystallization of Si-Mn, of which the MA rate was fastest, was studied by means of X-ray diffraction, differential thermal analysis (DTA) and electrical resistivity measurement. We observed parallel changes on crystallization between the thermal event in the DTA tracing and the change of electrical resistance.