The present invention provides a new artificial match-type miRNA utilizing miRNA.A single strand nucleic acid containing X region and Y region, wherein the 3'-terminal of the X region and the 5'-terminal of the Y region are linked via a linker region of a non-nucleotide structure, the X region contains a guide strand sequence of a mature miRNA, and the Y region contains a sequence completely complementary to the X region is an artificial match-type miRNA. The artificial match-type miRNA can suppress expression of the target gene.