A thermal rectifier comprising: a first panel; a second panel arranged to face the first panel; and a switching mechanism provided between the first panel and the second panel and configured to switch, according to respective temperatures of the first panel and the second panel, thermal conductivity between the first panel and the second panel, the switching mechanism including: a first thermally conductive portion thermally connected to the first panel; and a second thermally conductive portion thermally connected to the second panel, the first thermally conductive portion having a property of changing its hape or dimensions as its temperature varies characterised in that the second thermally conductive portion has a property of changing its shape or dimensions as its temperature varies, the switching mechanism being configured to, as the first thermally conductive portion and the second thermally conductive portion changes their shape or dimensions, switch from a heat radiation state where the first thermally conductive portion and the second thermally conductive portion are thermally coupled together to a heat insulation state where the first thermally conductive portion and the second thermally conductive portion are thermally isolated from each other, or vice versa. a first panel; a second panel arranged to face the first panel; and a switching mechanism provided between the first panel and the second panel and configured to switch, according to respective temperatures of the first panel and the second panel, thermal conductivity between the first panel and the second panel, the switching mechanism including: a first thermally conductive portion thermally connected to the first panel; and a second thermally conductive portion thermally connected to the second panel, the first thermally conductive portion having a property of changing its hape or dimensions as its temperature varies characterised in that the second thermally conductive portion has a property of changing its shape or dimensions as its temperature varies, the switching mechanism being configured to, as the first thermally conductive portion and the second thermally conductive portion changes their shape or dimensions, switch from a heat radiation state where the first thermally conductive portion and the second thermally conductive portion are thermally coupled together to a heat insulation state where the first thermally conductive portion and the second thermally conductive portion are thermally isolated from each other, or vice versa. a first thermally conductive portion thermally connected to the first panel; and a second thermally conductive portion thermally connected to the second panel, the first thermally conductive portion having a property of changing its hape or dimensions as its temperature varies characterised in that the second thermally conductive portion has a property of changing its shape or dimensions as its temperature varies, the switching mechanism being configured to, as the first thermally conductive portion and the second thermally conductive portion changes their shape or dimensions, switch from a heat radiation state where the first thermally conductive portion and the second thermally conductive portion are thermally coupled together to a heat insulation state where the first thermally conductive portion and the second thermally conductive portion are thermally isolated from each other, or vice versa.