A sheet transport device includes a transport unit that transports a sheet to a reading position by a first transport roller, a driving unit that switches a rotating direction, a rotating unit that rotates the first transport roller in one direction, the rotating unit including a one-direction gear that directly meshes with a first planet gear when the driving unit rotates in a first direction and meshes with a second planet gear when the driving unit rotates in a second direction, a switch unit that switches between states in which rotation of the one-direction gear is or is not transmitted to the first transport roller, and a displacement-force applying part that applies a force for displacing the first planet gear to mesh with the one-direction gear when the first planet gear touches the switch unit.

A sheet transport device includes a transport unit that transports a sheet to a reading position by a first transport roller, a driving unit that switches a rotating direction, a rotating unit that rotates the first transport roller in one direction, the rotating unit including a one-direction gear that directly meshes with a first planet gear when the driving unit rotates in a first direction and meshes with a second planet gear when the driving unit rotates in a second direction, a switch unit that switches between states in which rotation of the one-direction gear is or is not transmitted to the first transport roller, and a displacement-force applying part that applies a force for displacing the first planet gear to mesh with the one-direction gear when the first planet gear touches the switch unit.

A recording device 11 includes a device main body 20 including a recording section 25; a placement tray 21 on which a medium M is configured to be placed; and a cassette 22 provided below the recording section 25 and the placement tray 21 and configured to accommodate a medium M. The device main body 20 includes a first path 41 configured to feed medium M placed on the placement tray 21 to the recording section 25 and further to transport the recorded medium and a second path 42 configured to transport medium placed on the placement tray 21 to the cassette 22.

A recording device includes a device main body 20 including a recording section; a placement tray on which a medium M is configured to be placed; and a cassette provided below the recording section and the placement tray and configured to accommodate a medium M. The device main body includes a first path configured to feed medium M placed on the placement tray to the recording section and further to transport the recorded medium and a second path configured to transport medium placed on the placement tray to the cassette.