A technique capable of suppressing performance variation of every flow sensor and achieving performance improvement is provided. For example, in an arbitrary cross-sectional surface in parallel to a moving direction of a gas flowing on an exposed flow detecting unit FDU which is formed in a semiconductor chip CHP1, a sealing body is released from the lower mold BM by thrusting up, from a lower mold BM, an ejection pin EJPN arranged in an outer region of the semiconductor chip CHP1 so as not to overlap with the semiconductor chip CHP1 arranged in the vicinity of the center part. Thus, according to the first embodiment, the deformation applied to the sealing body at the time of mold releasing can be smaller than that in a case in which the sealing body is released from the lower mold BM by arranging the ejection pin EJPN in a region overlapping with the semiconductor chip CHP1.