A physical quantity measurement device includes a physical quantity detector and a support plate part superposed on a back surface of the physical quantity detector to support the physical quantity detector. The physical quantity detector includes a recessed part on the back surface, and a membrane part defining a bottom surface of the recessed part and being provided with a detection element for detecting a physical quantity of a fluid in a measurement low path. An area of the support plate part covering the recessed part includes a communication hole communicating with the recessed part. A peripheral edge portion of a hole opening, which is an end of the communication hole adjacent to the recessed part, is spaced apart, toward the inside, from a peripheral edge portion of a recess opening, which is an end of the recessed part adjacent to the support plate part.