There is provided a process for producing a prepolymerization catalyst for polymerization of an olefin, said process comprising the steps of feeding, to a polymerization reactor, an olefin and a solid catalyst component in which a catalyst component for polymerization of the olefin is carried on a fine particle support, and prepolymerizing the olefin in the presence of the solid catalyst component in the polymerization reactor, to thereby obtain the prepolymerization catalyst in which the olefin is prepolymerized on the solid catalyst component, characterized in that said solid catalyst component is pressure-fed to the polymerization reactor from a catalyst feeder connected to the polymerization reactor, and in that the inner pressure of the catalyst feeder at the start of the pressure-feeding is set at (Pr+0.0001) to (Pr+1) (MPa in unit) (in which Pr represents the inner pressure of the polymerization reactor (MPa in unit) at the start of the pressure-feeding).