A liquid flow path portion of a vapor chamber according to this invention includes a first main flow groove, a second main flow groove and a third main flow groove. A first convex array including a plurality of first convex portions arranged via a first communicating groove is provided between the first main flow groove and the second main flow groove. A second convex array including a plurality of second convex portions arranged via a second communicating groove is provided between the second main flow groove and the third main flow groove. The main flow groove includes a first intersection at which at least a part of the first communicating groove faces each second convex portion and a second intersection at which at least a part of the second communicating groove faces each first convex portion.