The first beam of a newly constructed ring cyclotron in RIKEN (Riken Ring Cyclotron; RRC) was successfully obtained in December, 1986. Theoretical and experimental studies concerning atomic collision problems by using RRC have been and are being made. The formulation and calculation of the radiative electron-capture process is being extensively studied theoretically. Experimental studies of radiative electron capture, multiple inner-shell ionization, and the charge distributions of 26 MeV/u Ar ions after passing through foils have also been made. The experimental facilities dedicated to atomic physics are also described.