A physical quantity sensor includes a base substrate; a movable unit which is provided so as to be displaced with respect to the base substrate by facing the base substrate; a first fixed electrode and a second fixed electrode which are disposed on the base substrate by facing the movable unit; and a plurality of protrusion portions which are disposed at a position overlapped with the movable unit in a planar view, on the movable unit side of the base substrate, in which the protrusion portion includes a conductive layer with the same potential as that of the first fixed electrode and the second fixed electrode, and an insulating layer which is provided on a side opposite to the base substrate with respect to the conductive layer.