A magnetic recording/reproducing apparatus including a detecting member which is operated to rotate a drive source disposed in a housing, and a slidable operating member for operating the detecting member. By simply pressing an indicator portion of the operating member with a small force from the front face side of the housing, the cartridge 4 is easily ejected by electrical power as a result of rotation of the drive source. In conventional magnetic recording/reproducing apparatuses, when the cartridge, loaded in the apparatus, is ejected therefrom, the back end of the cartridge must be firmly gripped to pull it out. Therefore, more force is required to pull out the cartridge than is required to insert it, making it very difficult to pull out the cartridge. The magnetic recording/reproducing apparatus of the invention overcomes this problem.