In a turbine scroll part structure of a radial turbine, a flow passage 3 of a connecting part between an exhaust gas inlet into a turbine housing 5 and a scroll part 1 is offset along an axis line L1 of a rotating shaft of a turbine rotor in an amount H, and a cut-out portion P is formed in a tongue portion 2, which separates the flow passage 3 from a blade side passage 4 through which the exhaust gas flows toward blades 6, for the exhaust gas to flow from the flow passage 3 into the blade side passage 4.