Disclosed is a novel substance capable of regulating the expression of a telomerase reverse transcriptase gene in a cell of a mammal. A gene capable of regulating the expression of hTERT, comprising a nucleotide sequence depicted in SEQ ID No: 1 or 2. The expression of a telomerase reverse transcriptase gene can be inhibited by inhibiting the expression of the gene. By utilizing this mechanism, the expression of a telomerase reverse transcriptase gene can be regulated.