A fixing heat dissipating unit that is disposed in an electronic device is connected to a substrate and a heat source. The fixing heat dissipating unit includes a fixing element and a heat conducting element. The fixing element is connected to the substrate to hold the substrate in the electronic device. The heat conducting element is respectively connected to the heat source and the fixing element. The heat source is a part of the electronic device and the fixing element is integrated with the heat conducting element as a single component. An electronic device having the fixing heat dissipating unit is also disclosed.