A valve gear in which corrosion due to a potential difference does not occur and which can reduce the corrosion occurrence even when loads due to microvibrations are given. The valve gear includes a valve stem and a valve bush that slidably supports the valve stem. The valve stem is formed from a forged part made of a Ni-based superalloy and the valve bush is formed from a cast part made of a Ni-based superalloy. The preferable surface roughness of a sliding surface of the valve stem in contact with the valve bush and the preferable surface roughness of a sliding surface of the valve bush in contact with the valve stem is 100 μM or less in units of Rz.