a semiconductor integrated circuit device comprises a semiconductor substrate ; an insulating layer formed on the semiconductor substrate ; a semiconductor layer insulated from the semiconductor substrate by the insulating layer ; source regions of a first conduction type and drain regions of the first conduction type both formed in the semiconductor layer ; body regions of a second conduction type formed in the semiconductor layer between the source regions and the drain regions to store data by accumulating or releasing an electric charge ; word lines formed on the body regions in electrical isolation from the body regions to extend in a first direction ; bit lines connected to the drain regions and extending in a direction different from the first direction ; and buried wirings formed in the insulating layer in electrical isolation from the semiconductor substrate and the semiconductor layer , said buried wirings extending in parallel with the bit lines .