A substrate is disclosed, which can remove heat from a stacked body of semiconductor elements through a phase change of a coolant. The substrate of the application includes: a stacked body of semiconductor elements; a first channel forming a path, receiving circulation of a first coolant, in a surface of the stacked body; and a second channel forming a path, receiving circulation of a second coolant having a boiling point higher than the boiling point of the first coolant, in an inter-layer portion of the stacked body.