To provide a layout structure of a clutch lever shaft capable of realizing compact layouts of a whole power unit in which a starter centrifugal clutch and a transmission manual multi-plate clutch are provided, and of a whole vehicle on which the power unit is mounted. A centrifugal clutch shaft and a manual multi-plate clutch shaft are disposed in parallel. The clutch lever shaft of the manual multi-plate clutch is disposed orthogonally and substantially vertically upward in relation to a pressing direction of a friction plate in a vicinity of an end portion of a lifter pin. The clutch lever shaft is disposed between the centrifugal clutch and the manual multi-plate clutch when viewed from a top of the power unit.