This study shows the development and performance assessment of a novel set-up that enables the research of structural materials for fusion reactors, by making possible simultaneous application of temperature (up to 450 °C) and magnetic field (close to 0.6 T) during irradiation experiments. These aspects become critical as structural materials in fusion reactors are exposed to intense radiation levels under the presence of strong magnetic fields. Moreover, material microstructure could be modified by radiation-induced propagating defects, which are thought to be sensitive to magnetic fields. The device has three main components: magnetic closure, sample holder with integrated heater, and radiation shield. It is provided with a thermal shield to prevent other elements of the device to heat up and fail. A mapping of the magnetic flux in the region where sample and heater are located has been modeled by finite elements simulation software and correlated with magnetic measurements.