A power train includes a gear mechanism, a rotating shaft fixing section, a transmission section, and a variable transmission section. The gear mechanism includes first and second planetary gear mechanisms. The first and second planetary gear mechanisms respectively include first to third rotating elements and fourth to sixth rotating elements which are each different to each other. The transmission section is able to transfer the drive force of the second rotating element to the fourth rotating element. The rotating shaft fixing section is able to integrally operate the rotating shafts of the third and fifth rotating elements. The variable transmission section includes an input section where drive force is input and an output section configured to output drive force equal to or less than the input drive force. A controller includes a connection modifying section and a drive force conversion control section. The connection modifying section integrally operates the rotating shafts of the third and fifth rotating elements using at least the rotating shaft fixing section. The drive force conversion control section controls the variable transmission section to enable the output of the engine to be converted to an appropriate drive force and the converted drive force to be transferred to the output shaft.
