A medium transport apparatus comprising: a power transmission apparatus; and a medium transport path (T1-T3) configured to transport a medium, the power transmission apparatus comprising: a drive source; a power transmission switching section configured to switch between a transmission state in which power of the drive source is transmitted to a driven section and a non-transmission state in which power of the drive source is not transmitted to the driven section; a load switching section configured to switch between a first load state, which is a load while the driven section is driven, and a second load state, which is a load smaller than the load of the first load state; and a control section configured to control the drive source, the power transmission switching section, and the load switching section, wherein the driven section is a drive roller configured to apply feeding force to the medium in the medium transport path, the medium transport apparatus further comprising a driven roller, characterized in that the driven roller is configured to advance and retreat with respect to the drive roller, the load switching section forms the first load state by bringing the driven roller into contact with the drive roller, and forms the second load state by separating the driven roller from the drive roller, and the control section switches the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, and then uses the load switching section to switch the load from the second load state to the first load state. a power transmission apparatus; and a medium transport path (T1-T3) configured to transport a medium, the power transmission apparatus comprising: a drive source; a power transmission switching section configured to switch between a transmission state in which power of the drive source is transmitted to a driven section and a non-transmission state in which power of the drive source is not transmitted to the driven section; a load switching section configured to switch between a first load state, which is a load while the driven section is driven, and a second load state, which is a load smaller than the load of the first load state; and a control section configured to control the drive source, the power transmission switching section, and the load switching section, wherein the driven section is a drive roller configured to apply feeding force to the medium in the medium transport path, the medium transport apparatus further comprising a driven roller, characterized in that the driven roller is configured to advance and retreat with respect to the drive roller, the load switching section forms the first load state by bringing the driven roller into contact with the drive roller, and forms the second load state by separating the driven roller from the drive roller, and the control section switches the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, and then uses the load switching section to switch the load from the second load state to the first load state. a drive source; a power transmission switching section configured to switch between a transmission state in which power of the drive source is transmitted to a driven section and a non-transmission state in which power of the drive source is not transmitted to the driven section; a load switching section configured to switch between a first load state, which is a load while the driven section is driven, and a second load state, which is a load smaller than the load of the first load state; and a control section configured to control the drive source, the power transmission switching section, and the load switching section, wherein the driven section is a drive roller configured to apply feeding force to the medium in the medium transport path, the medium transport apparatus further comprising a driven roller, characterized in that the driven roller is configured to advance and retreat with respect to the drive roller, the load switching section forms the first load state by bringing the driven roller into contact with the drive roller, and forms the second load state by separating the driven roller from the drive roller, and the control section switches the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, and then uses the load switching section to switch the load from the second load state to the first load state.