Crankshaft

The invention provides a crankshaft capable of improving a vibration reduction effect without greatly changing the design of a conventional crankcase. The mass of a first inner weight (21) on the center side of the rotation axis in a first crank section (6) on one end side of the rotation axis among the plurality of crank sections is formed larger than the mass of a first outer weight (20) on the end side of the rotation axis. The mass (23) of a second inner weight on the center side of the rotation axis in a second crank section (8) on the other end side of the rotation axis among the plurality of crank sections is formed larger than the mass of a second outer weight (22) on the end side of the rotation axis. 本发明提供一种曲轴，能够在不进行现有的曲轴箱的大幅的设计变更等的情况下提高振动降低效果的曲轴。多个曲柄部中的旋转轴线的一端侧的第一曲柄部(6)中的旋转轴线的中央侧的第一内侧配重(21)的质量形成得比旋转轴线的端部侧的第一外侧配重(20)的质量大，多个曲柄部中的旋转轴线的另一端侧的第二曲柄部(8)中的旋转轴线的中央侧的第二内侧配重的质量(23)形成得比旋转轴线的端部侧的第二外侧配重(22)的质量大。