A process for producing an olefin polymer, having a step comprising feeding an olefin polymerization catalyst solution, which is obtained by mixing at least one metallocene compound selected from a compound represented by the general formula and a compound represented by the general formula, a compound which is a compound that reacts with the metallocene compound to form an ion pair, and is represented by the general formula, and at least one compound selected from (C-1) an organoaluminum compound and (C-2) an organoaluminum oxy compound, with a saturated hydrocarbon solvent under the following conditions (i) to (iv), to a polymerization reactor and solution-polymerizing an olefin in the polymerization reactor; (i) the amount of the metallocene compound added to 1 liter of the saturated hydrocarbon solvent is 0.02 to 0.6 mmol, (ii) the molar ratio ( /) of an aluminum atom in the compound added to the saturated hydrocarbon solvent to the metallocene compound is 33 to 5000, (iii) the amount of an aluminum atom in the compound added to 1 liter of the saturated hydrocarbon solvent is 3 to 1000 mmol, and (iv) the molar ratio ( /) of the compound added to the saturated hydrocarbon solvent to the metallocene compound is 1 to 15; wherein, in the formulas and, M is an atom of the periodic table Group 4 or Group 5, Q is a halogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a neutral conjugated or non-conjugated diene, an anionic ligand or a neutral ligand capable of being coordinated with a lone electron pair, j is an integer of 1 to 4, when j is an integer of 2 or greater, plural Q may be the same as or different from each other, and Cp 1 and Cp 2 may be the same as or different from each other and are each a cyclopentadienyl group or a substituted cyclopentadienyl group capable of forming a sandwich structure together with M; and Y in the formula is a divalent hydrocarbon group of 1 to 30 carbon atoms, a divalent halogenated hydrocarbon group of 1 to 20 carbon atoms, a divalent silicon-containing group, a divalent germanium-containing group, a divalent tin-containing group, -O-, -CO-, -S-, -SO-, -SO 2 -, -Ge-, -Sn-, -NR a -, -P(R a) -, -P (R a)-, -BR a - or -AlR a - (wherein R a is a hydrocarbon group of 1 to 20 carbon atoms, a halogenated hydrocarbon group of 1 to 20 carbon atoms, a hydrogen atom, a halogen atom or a nitrogen compound residue in which one or two hydrocarbon groups of 1 to 20 carbon atoms are bonded to a nitrogen atom); wherein, in the formula, R e+ is carbenium cation, and R f to R i are each independently a hydrocarbon group of 1 to 20 carbon atoms or a halogenated hydrocarbon group of 1 to 20 carbon atoms. at least one metallocene compound selected from a compound represented by the general formula and a compound represented by the general formula, a compound which is a compound that reacts with the metallocene compound to form an ion pair, and is represented by the general formula, and at least one compound selected from (C-1) an organoaluminum compound and (C-2) an organoaluminum oxy compound, (i) the amount of the metallocene compound added to 1 liter of the saturated hydrocarbon solvent is 0.02 to 0.6 mmol, (ii) the molar ratio ( /) of an aluminum atom in the compound added to the saturated hydrocarbon solvent to the metallocene compound is 33 to 5000, (iii) the amount of an aluminum atom in the compound added to 1 liter of the saturated hydrocarbon solvent is 3 to 1000 mmol, and (iv) the molar ratio ( /) of the compound added to the saturated hydrocarbon solvent to the metallocene compound is 1 to 15; wherein, in the formulas and, M is an atom of the periodic table Group 4 or Group 5, Q is a halogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a neutral conjugated or non-conjugated diene, an anionic ligand or a neutral ligand capable of being coordinated with a lone electron pair, j is an integer of 1 to 4, when j is an integer of 2 or greater, plural Q may be the same as or different from each other, and Cp 1 and Cp 2 may be the same as or different from each other and are each a cyclopentadienyl group or a substituted cyclopentadienyl group capable of forming a sandwich structure together with M; and Y in the formula is a divalent hydrocarbon group of 1 to 30 carbon atoms, a divalent halogenated hydrocarbon group of 1 to 20 carbon atoms, a divalent silicon-containing group, a divalent germanium-containing group, a divalent tin-containing group, -O-, -CO-, -S-, -SO-, -SO 2 -, -Ge-, -Sn-, -NR a -, -P(R a) -, -P (R a)-, -BR a - or -AlR a - (wherein R a is a hydrocarbon group of 1 to 20 carbon atoms, a halogenated hydrocarbon group of 1 to 20 carbon atoms, a hydrogen atom, a halogen atom or a nitrogen compound residue in which one or two hydrocarbon groups of 1 to 20 carbon atoms are bonded to a nitrogen atom); wherein, in the formula, R e+ is carbenium cation, and R f to R i are each independently a hydrocarbon group of 1 to 20 carbon atoms or a halogenated hydrocarbon group of 1 to 20 carbon atoms.