In a scroll structure for a radial turbine configured such that a turbine rotor 02 is rotationally driven by causing exhaust gas to flow from a spiral scroll portion 4 formed in a turbine housing 1 toward a rotor blade 3 of the scroll portion 4 in a radial direction, and act on the rotor blade 3, then flow out in an axial direction, a heat radiation space portion is formed in a shroud portion 11 between the turbine housing 1 and a turbine chamber provided with the rotor blade 3.