A medium transport device includes a feeding unit that can be disposed at a contact position and a retracted position, a first restriction member that rotates between a restriction position and a release position, and a transport guide positioned on a side opposite to the feeding unit with a transport path interposed therebetween. When the first restriction member is positioned at the restriction position, the first restriction member maintains a state in which the feeding unit is positioned at the retracted position by the tip end contacting the feeding unit. When the first restriction member is positioned at the restriction position, the tip end thereof is positioned closer to the mounting portion side than the position of the rotation axis of the first restriction member in the transport direction.