To provide a modular electric apparatus of which the design a user can freely change and, which can, as a result, provide a new interior design with a feeling of unity.

The modular electric apparatus is provided with a housing box 10 made of synthetic resin, one or a plurality of connectors 20 installed on the side face of the housing box 10, a circuit board 30 which is installed in the housing box 10 and electrically connected to the connector 20, and an LED 50 which is installed in the housing box 10 and controlled by the circuit board 30 as a controlled part. A plurality of electric apparatuses 1 are electrically and mechanically connected to each other through the connector 20 in mutually attachable and detachable state.