A device embedded substrate (20), includes: an insulation layer (12) including an insulation resin material; an electric or electronic device (4) embedded in the insulation layer (12); a terminal (15) serving as an electrode included in the device (4); a conductor pattern (18) formed on the surface of the insulation layer (12); and a conducting via (21) for electrically connecting the conductor pattern (18) and the terminals (15) with each other. The conducting via (21) is made up of a large-diameter section (21a) having a large diameter and a small-diameter section (21b) having a smaller diameter than that of the large-diameter section (21a), in order starting from the conductor pattern (18) toward the terminal (15). A stepped section (17) is formed between the large-diameter section (21a) and the small-diameter section (21b). The large-diameter section (21a) is formed so as to penetrate a sheet-shaped glass cloth (11) disposed in the insulation layer (12).