To provide a strut structure and a gas turbine in which thermal stress is suppressed with a simple structure to permit the life span of a device to be extended.

The strut structure is equipped with a casing 7a formed in a tubular shape, an internal diffuser 7b provided inside the casing 7a formed in the tubular shape, a high-temperature fluid flow path 10b formed between the casing 7a and the internal diffuser 7b so that high-temperature fluid can pass therethrough, and a strut 9 which is formed in hollow and couples the casing 7a and the internal diffuser 7b to each other across the high-temperature fluid flow path 10b and further whose thickness t1 is set larger than a thickness t2 of the casing 7a. Accordingly, the strut structure and the gas turbine can be obtained in which the thermal stress is suppressed with a simple structure to permit the life span of the device to be extended.