To provide a physical quantity sensor in which the influence of deformation of a package substrate on the measuring accuracy of a sensor element can be suppressed. A physical quantity sensor includes a sensor element that detects a predetermined physical quantity and outputs an electrical signal, a plurality of lead portions that are connected to the sensor element, and a package substrate that accommodates the sensor element and the plurality of lead portions. The plurality of lead portions are connected at proximal end sides thereof to the package substrate side, and connected at distal end sides thereof to the sensor element side, and the plurality of lead portions support the sensor element in such a manner that the sensor element does not contact the package substrate and that the transmission of deformation of the package substrate side to the sensor element is suppressed.