A straddled vehicle comprising: a case; a partition wall that is arranged inside the case and partitions the inside of the case into a gear chamber and a breather chamber above the gear chamber; a first, second and third rotation shaft (41, 42, 43) that are rotatably supported on the case and extend in a vehicle width direction; a first gear that is provided on the first rotation shaft and arranged in the gear chamber; a second gear that is provided on the second rotation shaft, arranged in the gear chamber and meshes with the first gear; a third gear that is provided on the second rotation shaft and arranged in the gear chamber; and a fourth gear that is provided on the third rotation shaft, arranged in the gear chamber and meshes with the third gear, wherein a center of the second rotation shaft is arranged rearward of a center of the first rotation shaft; a center of the third rotation shaft is arranged rearward of the center of the second rotation shaft, characterized in that a lower end of the fourth gear is located below a lower end of the second gear; a front end of the breather chamber is located forward of a rear end of the first rotation shaft, and a rear end of the breather chamber is located rearward of a front end of the third rotation shaft; a hole that allows communication between the gear chamber and the breather chamber is formed at a position of the partition wall that is rearward of a front end of the fourth gear and forward of a rear end of the fourth gear; the hole is arranged rightward of a right end of the fourth gear or leftward of a left end of the fourth gear; and the hole does not overlap with the fourth gear, as the vehicle is seen from above. a case; a partition wall that is arranged inside the case and partitions the inside of the case into a gear chamber and a breather chamber above the gear chamber; a first, second and third rotation shaft (41, 42, 43) that are rotatably supported on the case and extend in a vehicle width direction; a first gear that is provided on the first rotation shaft and arranged in the gear chamber; a second gear that is provided on the second rotation shaft, arranged in the gear chamber and meshes with the first gear; a third gear that is provided on the second rotation shaft and arranged in the gear chamber; and a fourth gear that is provided on the third rotation shaft, arranged in the gear chamber and meshes with the third gear, wherein a center of the second rotation shaft is arranged rearward of a center of the first rotation shaft; a center of the third rotation shaft is arranged rearward of the center of the second rotation shaft, characterized in that a lower end of the fourth gear is located below a lower end of the second gear; a front end of the breather chamber is located forward of a rear end of the first rotation shaft, and a rear end of the breather chamber is located rearward of a front end of the third rotation shaft; a hole that allows communication between the gear chamber and the breather chamber is formed at a position of the partition wall that is rearward of a front end of the fourth gear and forward of a rear end of the fourth gear; the hole is arranged rightward of a right end of the fourth gear or leftward of a left end of the fourth gear; and the hole does not overlap with the fourth gear, as the vehicle is seen from above.