A polypeptide having a luciferase activity, the polypeptide being defined in any one of through below: a polypeptide which has (i) a mutation at an amino acid corresponding to a 347th amino acid in an amino acid sequence represented by SEQ ID NO: 1 and (ii) a sequence identity of 85% or more with respect to the amino acid sequence represented by SEQ ID NO: 1; a polypeptide which has (i) a mutation at an amino acid corresponding to the 347th amino acid in the amino acid sequence represented by SEQ ID NO: 1 and (ii) an amino acid sequence which is obtained by substitution, deletion, insertion, and/or addition of 1 to 82 amino acids with respect to the amino acid sequence represented by SEQ ID NO: 1; and a polypeptide which is encoded by a polynucleotide that hybridizes under stringent conditions with a polynucleotide consisting of a sequence complementary to a polynucleotide that encodes a polypeptide having the amino acid sequence represented by SEQ ID NO: 1 and which has a mutation at an amino acid corresponding to the 347th amino acid in the amino acid sequence represented by SEQ ID NO: 1, wherein hybridization under stringent conditions is conducted by incubating at 65°C for 8 to 16 hours together with a probe, in a solution that contains 6 × SSC (composition of 1 × SSC: 0.15 M of sodium chloride, 0.015 M of sodium citrate, pH 7.0), 0.5% of SDS, 5 × Denhardt's solution, and 100 mg/mL of herring sperm DNA and wherein the mutation at the amino acid corresponding to the 347th amino acid is a substitution to cysteine or asparagine and wherein, when the amino acid corresponding to the 347th amino acid is cysteine, an amino acid corresponding to the 229th amino acid is substituted with tyrosine or histidine, and wherein in the polypeptide, substrate specificity to at least one other-color luminescent substrate other than D-luciferin has been improved as compared with D-luciferin. a polypeptide which has (i) a mutation at an amino acid corresponding to a 347th amino acid in an amino acid sequence represented by SEQ ID NO: 1 and (ii) a sequence identity of 85% or more with respect to the amino acid sequence represented by SEQ ID NO: 1; a polypeptide which has (i) a mutation at an amino acid corresponding to the 347th amino acid in the amino acid sequence represented by SEQ ID NO: 1 and (ii) an amino acid sequence which is obtained by substitution, deletion, insertion, and/or addition of 1 to 82 amino acids with respect to the amino acid sequence represented by SEQ ID NO: 1; and a polypeptide which is encoded by a polynucleotide that hybridizes under stringent conditions with a polynucleotide consisting of a sequence complementary to a polynucleotide that encodes a polypeptide having the amino acid sequence represented by SEQ ID NO: 1 and which has a mutation at an amino acid corresponding to the 347th amino acid in the amino acid sequence represented by SEQ ID NO: 1, wherein hybridization under stringent conditions is conducted by incubating at 65°C for 8 to 16 hours together with a probe, in a solution that contains 6 × SSC (composition of 1 × SSC: 0.15 M of sodium chloride, 0.015 M of sodium citrate, pH 7.0), 0.5% of SDS, 5 × Denhardt's solution, and 100 mg/mL of herring sperm DNA and wherein the mutation at the amino acid corresponding to the 347th amino acid is a substitution to cysteine or asparagine and wherein, when the amino acid corresponding to the 347th amino acid is cysteine, an amino acid corresponding to the 229th amino acid is substituted with tyrosine or histidine, and wherein in the polypeptide, substrate specificity to at least one other-color luminescent substrate other than D-luciferin has been improved as compared with D-luciferin. <EOS>