A magnetic resonance imaging system is provided wherein measurement data (k space data) is extracted easily (and instantaneously) after imaging a plurality of times phases, and an image can be displayed in dynamic MRA measurement employing a contrast medium. Dynamic measurement is carried out, including extracting the time phase evaluation values (e.g. the origin data in k space) in respective time phases and then automatically extracting a data set including a time phase where the time phase evaluation value reaches a specified threshold value.