To provide a method for producing a catalyst component, which improves the whole of catalyst performance such as stereoregularity and catalyst activity, and further controls the average particle diameter and particle size distribution or the like of a catalyst for obtaining the desired average particle diameter and particle size distribution regarding polymer particles without damaging the productivity of an α-olefin production process.

The method for producing a solid catalyst component for α-olefin polymerization or the like are characterized in that, regarding a solution including a magnesium compound and a titanium compound as solutes, the precipitation of particles is caused with a precipitation agent in a stirring tank provided with at least one or more stirrers and one or more baffles, and thereafter, treatment is performed with a halogen compound.