An electrical connection box includes a plurality of circuit components at least partially overlapped one above the other and substantially parallel with each other each circuit component having a substrate including a switching member and an electric power conducting path; and a supporting member that retains the circuit components. The switching member capable of attaching and detaching is arrayed on an upper plane of an upper substrate. The electric power conducting path of a lower circuit component is provided with a terminal connectable by extending above the upper substrate with the switching member.