Stepped automatic transmission device, power unit with the transmission device, and motorcycle with the power unit

[Problem] To provide a transmission, which is compact in an axial direction of an input shaft and in which a distance between the input shaft and an output shaft is relatively short. [Means for Resolution] A transmission 31 includes a first rotating shaft 53, a second rotating shaft 54, and a third rotating shaft 64, each of which is arranged in a direction perpendicular to an axial direction of an input shaft 52, a first clutch 55, a first change gear pair 86 including a first gear 58 and a second gear 63, which rotate together with an output side clutch member 57, a first transmission gear pair 84 including a third gear 87, which rotates together with the first rotating shaft 53, and a fourth gear 75, a second transmission gear pair 85 including a fifth gear 74, which rotates together with the second rotating shaft 54, and a sixth gear 78, a second clutch 70, and a second change gear pair 91 including a seventh gear 73, which rotates together with an output side clutch member 72, and an eighth gear 77. At least one of an axis C2 and an axis C4 is not present in a plane P.