Provided is a heat dissipation device. The heat dissipation device includes a thermal conductive plate (1), a shape of which is the same as a shape of a Secure Digital (SD) card. The thermal conductive plate (1) is used to be inserted into an SD card connector, and partially contacts with at least one inner surface of the SD card connector; the thermal conductive plate (1) is made of thermal conductive metallic material, and one or more contacting parts (10) of the thermal conductive plate (1) that contact with the SD card connector are set to be thermal conductive metallic material, and outer surfaces (12), other than the one or more contacting parts (10), of the thermal conductive plate (1) are set to be insulating material. The present technical solution solves the problem that the implementing effect of heat dissipation schemes already existed for terminals is fairly bad in the related technologies, and improves heat conduction and heat dissipation speed. The heat dissipation device occupies less space in the terminal, and enhances heat dissipation efficiency.