ELECTRONIC COMPONENT BUILT-IN SUBSTRATE, MANUFACTURING METHOD OF ELECTRONIC COMPONENT BUILT-IN SUBSTRATE, AND LAMINATION TYPE ELECTRONIC COMPONENT BUILT-IN SUBSTRATE

PROBLEM TO BE SOLVED: To provide an electronic component built-in substrate having a new structure that deals with the thickness reduction when the electronic component built-in substrate is laminated.SOLUTION: An electronic component built-in substrate 1 includes: a wiring layer 50; an electronic component 30 electrically connected with the wiring layer 50; a first electrode 20 provided on the wiring layer 50 and electrically connected with the wiring layer 50; a metal joint material 22 provided on the first electrode 20; a second electrode 56 provided below the wiring layer 50 and protruding downward from the wiring layer; and an insulation part 40 where the electronic component 30, the first electrode 20, and the metal joint material 22 are embedded. When the electronic component built-in substrate 1 is laminated on another electronic component built-in substrate 1, the second electrode 56 is embedded in the metal joint material 22 to be joined thereto.