There is disclosed a heat radiation device for memory modules intended for radiating heat that is generated from a memory module group wherein a plurality of memory modules equipped with memory elements on both the front and rear face sides of a substrate are placed in parallel. The device comprises heat radiation plates in pairs composed of front face side heat radiation plates in contact with memory elements that are installed on the front face side of the substrate for each of the memory modules, and of rear face side heat radiation plates in contact with memory elements that are installed on the rear face side of the substrate; and connecting members for heat radiation plates in pairs which connect the heat radiation plates in pairs so that heat is conducted among a plurality of the heat radiation plates in pairs.