Cash transaction machine and method for rejecting paper medium in cash transaction machine

An automatic teller machine and a medium rejecting method of the automatic teller machine are provided to form a large reject box by sparing a space for a reject returning path in the reject box. A first medium transfer device(130) transfers the paper medium from a medium storage(120) by a sheet unit. A temporary stack unit is adjacent to the exit of a first medium transfer device and has a support. The support stacks the paper medium and move up and down. A second medium transfer device receives the paper medium from the rising support and transfers the paper medium to the medium exit. A reject unit(190) is positioned in the lower part of the support and provides the reject inlet to move vertically with the support. When the paper medium is rejected, the support rises to make the reject inlet position adjacently to the outlet of the first medium transfer device. The reject unit includes a reject returning path and a reject box. The reject returning path is mounted in the lower part of the support and move vertically with the support.