To reduce the size of a substrate wherein at least two electronic components are connected by bump on its surface, and to prevent or reduce the problem caused by the contact of an underfill with another surface mounting part that is applied between its surface and an electronic components and protruded therefrom.

The substrate is provided with at least two electronic components on its surface that are bump-connected. When an underfill is supplied between the electronic components and the surface, the electronic components are respectively arranged in a space regulated by the side surface of one electronic component, that of the other electronic component and the surface at such a spacing that reinforcing resin fillets can be formed as being common to the respective electronic components.