To provide a steering damping mechanism of a motorcycle for evenly affecting a magnetic field to magnetic fluid.

The steering damper (steering damping mechanism) includes a steering shaft 5 rotating together with rotation of a handlebar 4 and supported to a hollow part 2a of a head pipe 2 to rotate freely, an oil chamber 14 formed between the head pipe 2 and the steering shaft 5 to surround the periphery of the steering shaft 5 and filled with the magnetic fluid of which the viscosity becomes larger by the effect of the magnetic field, and a coil part 17 disposed to surround the periphery of the oil chamber 14 and applying the magnetic field to the magnetic fluid in the oil chamber 14.