Provided is an electronic circuit unit which includes a circuit board, a case for the circuit board and a connector for external connection and can be miniaturized and simplified in structure. This electronic circuit unit includes a circuit board (10) provided with a plurality of conductors for connection (14) on an edge part (12), a case (CS) configured to house the circuit board, and a plurality of terminals (30) provided on ends of a plurality of wires (W). The case (CS) integrally includes a board housing portion (20) and a terminal holding portion (40). The board housing portion (20) holds the circuit board (10) at a specific board holding position. The terminal holding portion (40) holds these terminals (30) in such an arrangement that each terminal (30) comes into contact with each conductor for connection (14) of the circuit board (10) at the board holding position.