Gravitational-wave detector LIGO first detected the gravitational-wave signals in 2015, and then 90 compact binary coalescences were detected until March 2020. These detections provide new eyes to observe the universe and promote our understandings of the universe. For further promotions, precise localization of gravitational-wave sources is essential, which will be accomplished by observing the signals with more gravitational-wave detectors simultaneously. KAGRA is a kilometer-scale interferometric gravitational-wave detector located in Japan. There are two unique features in KAGRA: utilizing an underground site and cooling four main sapphire mirrors at cryogenic temperature. Underground site has a quiet environment, which results in the reduction of seismic noise. Cryogenic mirrors reduce thermal noise of mirrors and their suspensions, which is one of the fundamental noise sources that limit the sensitivity of interferometric gravitational-wave detectors. These features are considered as the fundamental technologies for the next-generation gravitational-wave detectors to obtain further sensitivity; and therefore our experiences on utilizing the underground site and cryogenic mirrors can indicate the way for their development. KAGRA joined the fourth international observing run from 24th of May to 21st of June in 2023. During the observing run, we achieved higher sensitivity and stability compared with those in the previous international observing run on April 2020. In this presentation, the current status of KAGRA is reported.