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 is selected from plural types of tape cassettes accommodating tape recording media with differing widths. The magnetic recording/reproducing apparatus includes a rotating drum unit with a rotating head, and a loading mechanism that pulls the tape recording medium of the loaded tape cassette out of the loaded tape cassette, winds the tape recording medium of the loaded tape cassette around the rotating drum unit over a winding angle, and forms a tape path. The loading mechanism adjusts the winding angle for winding the tape recording medium of the loaded tape cassette according to the width of the tape recording medium of the loaded tape cassette.