An automatic teller machine (ATM) including 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 as a storage space, and a medium alignment portion disposed on a transfer path of the medium transfer portion to align the paper medium. The medium alignment portion includes 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 to align the paper medium; driving rollers disposed in the alignment body to drive the paper medium forward along the transfer path; and inclined rollers disposed outside of the alignment body corresponding to the driving rollers, and selectively inclined from a transfer direction of the paper medium.