The present invention relates to an asymmetric siRNA which inhibits an expression of male pattern hair loss target genes and a use thereof and, more particularly, to an asymmetric siRNA which inhibits an expression of 3-oxo-5-alpha-steroid-4-dehydrogenase 1 (SRD5A1) gene, 3-oxo-5-alpha-steroid-4-dehydrogenase 2 (SRD5A2) gene or androgen receptor (AR) gene, and a composition for prevention or treatment of hair loss comprising the asymmetric siRNA.