A rotary mold type injection molding machine and a method for exchanging molds of a rotary mold type injection molding machine. The rotary mold type injection molding machine includes a fixed platen, a movable platen which is opened and closed in a horizontal direction with respect to the fixed platen, and a rotary table to which a plurality of molds is mounted and which is rotatably provided on one of the fixed platen and the movable platen. The rotary mold type injection molding machine further includes: a mold member which is configured of a plurality of molds and mold mounting plates to which the plurality of molds is mounted; and a mounting portion which is provided on the rotary table provided on one of the fixed platen and the movable platen and on which the mold mounting plate is mounted when the mold member is fixed.