A flow sensor structure seals the surface of an electric control circuit and part of a semiconductor device via a manufacturing method that prevents occurrence of flash or chip crack when clamping the semiconductor device via a mold. The flow sensor structure includes a semiconductor device having an air flow sensing unit and a diaphragm, and a board or lead frame having an electric control circuit for controlling the semiconductor device, wherein a surface of the electric control circuit and part of a surface of the semiconductor device is covered with resin while having the air flow sensing unit portion exposed. The flow sensor structure may include surfaces of a resin mold, a board or a pre-mold component surrounding the semiconductor device that are continuously not in contact with three walls of the semiconductor device orthogonal to a side on which the air flow sensing unit portion is disposed.