To provide a heat recovery device for a waste incinerator that can recover waste heat efficiently without causing molten salt corrosion even from exhaust gas of a waste incinerator including high density chlorine gas.

The heat recovery device has many heat exchanger tubes 5 arranged in a can 1 into which chlorine including high temperature exhaust gas emitted from a waste incinerator is introduced. The heat exchanger tubes 5 have a structure wherein a metal tube 7 is externally protected with an SiC tube 8 and the gap between them is filled with highly heat-conductive mortar 9 such as SiC mortar. The highly heat-conductive mortar 9 preferably comprises SiC including Si and preferably has a thermal conductivity of 100 kcal/m2h°C or higher.