In the interior of a resin mold portion that constitutes a fuel injection valve, an amplifying member to which a power source terminal and a signal terminal are connected, is provided. A signal transmitting unit, which outputs a detection signal from a sensor, is connected electrically to a substrate of the amplifying member. Further, the amplifying member is molded integrally when the resin mold portion is formed. In addition, a pressure inside a combustion chamber of an internal combustion engine, which is detected by the sensor, is output through the signal transmitting unit to the amplifying member, is amplified by the amplifying member, and is output externally from the signal terminal.