Abstract: A flywheel with a torsional damper having two kinds of spring mechanisms, one spring mechanism directly connecting driving and driven side flywheels and the other spring mechanism connecting the driviing and driven side flywheels via a friction mechanism. By this arrangement, the flywheel has two vibrational characteristics between which vibrational operation of the flywheel can shift depending on whether the friction mechanism slides. The flywheel can pass through its resonance speed by shifting its operation from one vibrational characteristic to the other without being accompanied by a large amplification of vibration. In addition, since sliding at the friction mechanism occurs only briefly, a good damping effect can be obtained at the usual range of engine operating speeds unlike a prior art flywheel with a continuously sliding hysteresis mechanism.