MicroRNA, a biomarker for various diseases, was diagnosed by electrical monitoring of its transit event through a biological nanopore. The target microRNA in a sample solution selectively forms a duplex with a complementary DNA specially designed, which makes the transit time to slow down. An artificial lipid bilayer device previously reported allowed to implement the nanopore platform just by sequential injection of aqueous and lipid/oil solutions. A series of feasibility tests demonstrated rapid, selective, and label-free detection of the target microRNA with the simple operation. Further development on the limited sensitivity will offer a possible future application for the onsite diagnosis.