Multilayer substrate

A multilayer substrate (10) is provided with: a component mounting electrode (121) connected to an electronic component (2); an external mounting electrode (124) connected to an external structure; and a heat dissipation part (16) comprising through-conductors (141, 1421, 1422, 143) stacked in the layering direction between the component mounting electrode (121) and the external mounting electrode (124), wherein the heat dissipation part (16) is provided with connecting parts (161, 162) in which one through-conductor extends in each ceramic layer and a branching part (163) in which multiple through-conductors extend in between the connecting parts (161, 162) in each ceramic layer, and the position at which the through-conductors of the connecting parts (161, 162) and the through-conductors of the branching part (163) adjoin one another is separate from the central position of each through-conductor as seen from the layering direction. 本发明的多层基板(10)包括：与电子元器件(2)相连接的元器件安装电极(121)；与外部结构相连接的外部安装电极(124)；以及连接在元器件安装电极(