A medium storage box comprising: a first supporting plate for storing first medium; and a second supporting plate spaced apart from the first supporting plate, for storing second medium, characterized by: a pickup roller, disposed between the first supporting plate and the second supporting plate, for selectively picking up one of the first medium on the first supporting plate and the second medium on the second supporting plate; a pushing plate pushing the second medium on the second supporting plate toward the pickup roller to pick up the second medium; a connecting plate connected to a rotation axis of the pickup roller; and an elastic member providing an elastic force to the connecting plate, the elastic force allowing the rotation axis to be moved toward the first supporting plate; wherein the first supporting plate is located below the pickup roller, wherein the second supporting plate is arranged above the pickup roller, and wherein the second supporting plate is provided with a hole where the pickup roller penetrates; wherein, when the second medium is withdrawn, the first supporting plate provides a pushing force toward the pickup roller in such a way that the rotation axis is rotated together with the connecting plate, and wherein the connecting plate is fastened by a fastening part at a position where the connecting plate is moved. a first supporting plate for storing first medium; and a second supporting plate spaced apart from the first supporting plate, for storing second medium, characterized by: a pickup roller, disposed between the first supporting plate and the second supporting plate, for selectively picking up one of the first medium on the first supporting plate and the second medium on the second supporting plate; a pushing plate pushing the second medium on the second supporting plate toward the pickup roller to pick up the second medium; a connecting plate connected to a rotation axis of the pickup roller; and an elastic member providing an elastic force to the connecting plate, the elastic force allowing the rotation axis to be moved toward the first supporting plate; wherein the first supporting plate is located below the pickup roller, wherein the second supporting plate is arranged above the pickup roller, and wherein the second supporting plate is provided with a hole where the pickup roller penetrates; wherein, when the second medium is withdrawn, the first supporting plate provides a pushing force toward the pickup roller in such a way that the rotation axis is rotated together with the connecting plate, and wherein the connecting plate is fastened by a fastening part at a position where the connecting plate is moved. a pickup roller, disposed between the first supporting plate and the second supporting plate, for selectively picking up one of the first medium on the first supporting plate and the second medium on the second supporting plate; a pushing plate pushing the second medium on the second supporting plate toward the pickup roller to pick up the second medium; a connecting plate connected to a rotation axis of the pickup roller; and an elastic member providing an elastic force to the connecting plate, the elastic force allowing the rotation axis to be moved toward the first supporting plate; wherein the first supporting plate is located below the pickup roller, wherein the second supporting plate is arranged above the pickup roller, and wherein the second supporting plate is provided with a hole where the pickup roller penetrates; wherein, when the second medium is withdrawn, the first supporting plate provides a pushing force toward the pickup roller in such a way that the rotation axis is rotated together with the connecting plate, and wherein the connecting plate is fastened by a fastening part at a position where the connecting plate is moved.