A drum base according to he invention, on which a drum of a magnetic tape recorder is mounted, comprises a substantially annular frame having a fixing surface to which the drum is fixed; at least one through hole extending through the fixing surface for allowing a screw which is to be threadably attached to a threaded hole formed in the drum to pass therethrough; and a pair of mounting surfaces provided on the fixing surface on which the drum is mounted, the mounting surfaces being located adjacent to the at least one through hole so as to have a symmetrical relationship in a circumferential direction of the annular frame with respect to the at least one through hole and within a range of a diameter dimension of the at least one through hole in a radial direction of the annular frame.