The physical quantity sensor includes a substrate of which thickness direction is in the direction along the Z axis, and a sensor element provided on the substrate to detect a physical quantity, wherein the sensor element includes a movable part which is displaced in a direction along the X axis that is an axis for measuring the physical quantity with respect to the substrate, and a fixed electrode fixed to the substrate, and the movable part includes a movable electrode disposed to face the fixed electrode in the direction along the X axis, and a mass portion that supports the movable electrode and has a longer length than the movable electrode in a direction along the Z axis.