A sensor device is composed of a sensor element having a sensing portion, and a signal-outputting portion mounted on a substrate. The sensor element is also mounted on the substrate via a resilient material. The sensor element is electrically connected to the signal-outputting portion through a bonding wire. The work consisting of the sensor element, signal-outputting portion and the substrate is held in a molding die, and the work is molded with an insulating material, while keeping the sensing portion exposed outside of the insulating material. A depressed portion of the molding die, in which the sensor element is accommodated in the molding process, has substantially no clearance relative to the sensor element, and the sensor element is led to the depressed portion by resiliency of the material bonding the sensor element to the substrate. Therefore, no burs are formed on the sides of the sensor element in the molding process.