To provide a system which can supply electric power to a group of modules, the connected relation between which can be changed dynamically.

Each of modules 124 and 126 has connecting plates on four side faces and each plate is provided with two kinds of lead sections 128, namely, a projecting positive lead section and a non-projecting negative lead section. When the module 124 is connected to a power source 122, the lead section of the left-side plate of the module 124 is connected to the positive and negative electrodes of the power source 122 and becomes a route and the plates on the other side faces become branch plates. When the module 126 is connected to the module 124, the left-side plate of the module 126 becomes a route. At the contacting plates of the modules 124 and 126, by having the positive lead section of the contact plate of one module push in the negative lead section of the contact plate of the other module, and as a result, a switch 129 of the other module is opened and a single-loop circuit is formed.