A magnetic recording/reproducing apparatus is disclosed that is arranged to receive a tape cassette accommodating a tape recording medium that is selectively loaded thereto, the loaded tape cassette being selected from plural different types of tape cassettes of different sizes. The apparatus includes a rotating drum unit having a rotating head, and plural loading poles that are configured to pull the tape recording medium of the loaded tape cassette out of the loaded tape cassette, wind the tape recording medium of the loaded tape cassette around the rotating drum unit, and form a tape path. The loading poles include a common loading pole that is used when any one of the different types of tape cassettes is loaded, and an individual loading pole that is used when a predetermined type of tape cassette of the different types of tape cassettes is loaded.