To provide an electrical components mounting substrate which does not need a wide substrate area and reduces cost in order to cope with a plurality of systems which are alternatively and not simultaneously selected, the electrical components mounting substrate being able to mount the electrical components corresponding to the systems.

In an electrical components mounting substrate 1 on which a plurality of electrical components are mounted, individual mounting patterns 2, 3 of the components, which are alternatively and not simultaneously selected, are disposed at a single position.