A method for manufacturing a device embedded substrate in which an IC device is embedded, the IC device having a first surface side with a first terminal provided on and an opposite, second surface side with a second terminal provided on, the second surface side being structurally weaker than the first surface side, the method comprising: a preparation step of preparing a support plate where a metal film is formed on a surface; a mounting step of mounting the IC device by joining the first terminal onto a surface of the metal film via an adhesive layer; a first insulating layer formation step of forming a first insulating layer in which the IC device is embedded by laminating an insulating resin material so as to cover the metal film and the IC device; an inner metal layer formation step of forming an inner metal layer on a surface of the first insulating layer; an interconnection pattern formation step of removing the support plate, and then, forming a first terminal interconnection pattern by electrically connecting the first terminal and the metal film; a second insulating layer formation step of forming a second insulating layer by laminating an insulating resin material so as to cover the inner metal layer; an outer metal layer formation step of forming an outer metal layer on a surface of the second insulating layer; and a conductive via formation step of forming a conductive via (16, 22) that electrically connects the outer metal layer and the second terminal by forming a via (15, 21) that penetrates the first insulating layer and the second insulating layer from the outer metal layer to reach the second terminal and filling a conductor into the via (15, 21), characterized in that the first terminal is at least one of a source terminal and a gate terminal, and the second terminal is a drain terminal. a preparation step of preparing a support plate where a metal film is formed on a surface; a mounting step of mounting the IC device by joining the first terminal onto a surface of the metal film via an adhesive layer; a first insulating layer formation step of forming a first insulating layer in which the IC device is embedded by laminating an insulating resin material so as to cover the metal film and the IC device; an inner metal layer formation step of forming an inner metal layer on a surface of the first insulating layer; an interconnection pattern formation step of removing the support plate, and then, forming a first terminal interconnection pattern by electrically connecting the first terminal and the metal film; a second insulating layer formation step of forming a second insulating layer by laminating an insulating resin material so as to cover the inner metal layer; an outer metal layer formation step of forming an outer metal layer on a surface of the second insulating layer; and a conductive via formation step of forming a conductive via (16, 22) that electrically connects the outer metal layer and the second terminal by forming a via (15, 21) that penetrates the first insulating layer and the second insulating layer from the outer metal layer to reach the second terminal and filling a conductor into the via (15, 21), characterized in that the first terminal is at least one of a source terminal and a gate terminal, and the second terminal is a drain terminal.