To provide an electronic-component mounting substrate that allows an electronic component to be firmly fixed to a mounting part via an adhesive even if a conductor layer, whose uppermost surface is a gold-plating layer, is formed onto the mounting part, and also, that facilitates manufacturing of an electronic device having excellent reliability.

The electronic-component mounting substrate 9 is configured so that a conductor layer 2, whose uppermost surface is a gold-plating layer 2a, is formed onto an electronic-component mounting part 1a on an insulating substrate 1 and an electronic component 5 is mounted on the gold-plating layer 2a and fixed via an adhesive 6. A base plating layer 2b of the gold-plating layer 2a includes ceramic powder 4 partially exposed on the surface of the gold-plating layer 2a. The adhesive 6 can be firmly adhered onto the surface of the gold-plating layer 2a by the ceramic powder 4 exposed on the surface. Accordingly, it is possible to firmly bond the electronic component 5 to the mounting part 1a via the adhesive 6.