An automatic teller machine comprising a medium receiving portion to receive a paper medium, a medium transfer portion to transfer the paper medium received through the medium receiving portion to a cassette (117, 118, 119) functioning as a storage space, and a medium alignment portion disposed on a transfer path of the medium transfer portion to align the paper medium, wherein the medium alignment portion comprises: a drum-type alignment body including a transfer path connected to the transfer path of the medium transfer portion so that the paper medium passes through the transfer path in a rotating manner, and including an alignment reference surface for alignment of the paper medium; a plurality of driving rollers disposed in the alignment body to drive the paper medium forward along the transfer path; and a plurality of inclined rollers disposed at an outside of the alignment body to correspond to the plurality of driving rollers, and selectively inclined with respect to a transfer direction of the paper medium, wherein the alignment body comprises: a first body formed in a drum shape, through which the paper medium is passed in a rotating manner and in which the plurality of driving rollers are mounted; and a second body disposed at one side of the first body and formed to have a diameter greater than a diameter of the first body, the second body of which a surface directed to the first body is defined as the alignment reference surface, wherein the alignment reference surface comprises a plurality of grooves formed along a circumference of the alignment reference surface to prevent folding of one side of the paper medium which contacts the alignment reference surface, and wherein the medium alignment portion further comprises inclination adjustment portions connected to the plurality of inclined rollers, respectively, to adjust an inclination of the plurality of inclined rollers with respect to the transfer direction of the paper medium, characterized in that the first body is fixed to the housing while the second body is rotatable with respect to the first body corresponding to a driving speed of the paper medium. a drum-type alignment body including a transfer path connected to the transfer path of the medium transfer portion so that the paper medium passes through the transfer path in a rotating manner, and including an alignment reference surface for alignment of the paper medium; a plurality of driving rollers disposed in the alignment body to drive the paper medium forward along the transfer path; and a plurality of inclined rollers disposed at an outside of the alignment body to correspond to the plurality of driving rollers, and selectively inclined with respect to a transfer direction of the paper medium, wherein the alignment body comprises: a first body formed in a drum shape, through which the paper medium is passed in a rotating manner and in which the plurality of driving rollers are mounted; and a second body disposed at one side of the first body and formed to have a diameter greater than a diameter of the first body, the second body of which a surface directed to the first body is defined as the alignment reference surface, a first body formed in a drum shape, through which the paper medium is passed in a rotating manner and in which the plurality of driving rollers are mounted; and a second body disposed at one side of the first body and formed to have a diameter greater than a diameter of the first body, the second body of which a surface directed to the first body is defined as the alignment reference surface, wherein the alignment reference surface comprises a plurality of grooves formed along a circumference of the alignment reference surface to prevent folding of one side of the paper medium which contacts the alignment reference surface, and wherein the medium alignment portion further comprises inclination adjustment portions connected to the plurality of inclined rollers, respectively, to adjust an inclination of the plurality of inclined rollers with respect to the transfer direction of the paper medium, characterized in that the first body is fixed to the housing while the second body is rotatable with respect to the first body corresponding to a driving speed of the paper medium.