Quantum Gravity Through Non-Perturbative Renormalization Group and Improved Black Hole

Usually, General Relativity (GR) is known to be unrenormalizable perturbatively from the viewpoint of quantum field theory. But in the modern sense of renormalizability, there still remains the possibility to investigate whether GR is “nonpertubatively” renormalizable or not. Here I review the basics and results in this topic based on the “Effective Average Action” approach which was proposed by M.Reuter, and discuss its application to the balck hole geometry.