In a power transmission apparatus, a second clutch includes a divider dividing driving clutch plates and driven clutch plates in an axial direction such that a first region adjacent to a clutch pressure plate and a second region adjacent to a centrifugal clutch are defined. The second clutch presses the driving clutch plates and the driven clutch plates in the first region and the second region against each other during operation of the centrifugal clutch, and presses the driving clutch plates and the driven clutch plates in the first region against each other during operation of a back torque transmission cam.