We performed Ξ hypernuclear spectroscopy with the (K−, K+) reaction at J-PARC to investigate the ΞN interaction (J-PARC E05). A new experiment (J-PARC E70) in which a better energy resolution could be achieved is now being prepared. In this article, an analysis status of J-PARC E05 and a preparation status of J-PARC E70 are described.