A flexible substrate and an electronic device having high flexibility as a whole including an element mounting portion and a connection terminal portion, and a production method of the electronic device are provided. The flexible substrate includes a flexible base, and a conductive wiring made of a conductive organic compound formed on the base, wherein part of the conductive wiring serves as a connection part with another electronic member. Further, an electronic device 100 includes flexible bases 11 and 21, conductive wirings 13 and 23 made of a conductive organic compound formed on the bases, and electronic elements 12 and 22 connected to the conductive wirings, wherein part of the conductive wiring serves as a connection part 30 with another substrate.