An acceleration sensor comprising: a substrate; a fixing portion formed on the substrate; a mass body that includes a first portion provided on one side of the fixing portion and a second portion provided on the other side of the fixing portion, is formed on the substrate, and is displaceable in a thickness direction of the substrate; a beam that is formed on the substrate and connects the fixing portion and the mass body to each other; a first fixed electrode disposed at a position facing the first portion; and a second fixed electrode disposed at a position facing the second portion, wherein a first surface of the substrate is a surface facing the first fixed electrode and the second fixed electrode, wherein a second surface of the substrate is a surface opposite to the first surface, wherein a value obtained by multiplying a distance between a first center of gravity of the first portion and a center of the fixing portion by a mass of the first portion is greater than a value obtained by multiplying a distance between a second center of gravity of the second portion and a center of the fixing portion by a mass of the second portion, wherein a first number of first opening portions are formed in a region corresponding to the first portion of the mass body, on the first surface of the substrate, wherein a second number of second opening portions are formed in a region corresponding to the first portion of the mass body, on the second surface of the substrate, wherein the first opening portion and the second opening portion are connected to each other to form a plurality of first through portions in the substrate, and wherein the first number is greater than the second number. a substrate; a fixing portion formed on the substrate; a mass body that includes a first portion provided on one side of the fixing portion and a second portion provided on the other side of the fixing portion, is formed on the substrate, and is displaceable in a thickness direction of the substrate; a beam that is formed on the substrate and connects the fixing portion and the mass body to each other; a first fixed electrode disposed at a position facing the first portion; and a second fixed electrode disposed at a position facing the second portion, wherein a first surface of the substrate is a surface facing the first fixed electrode and the second fixed electrode, wherein a second surface of the substrate is a surface opposite to the first surface, wherein a value obtained by multiplying a distance between a first center of gravity of the first portion and a center of the fixing portion by a mass of the first portion is greater than a value obtained by multiplying a distance between a second center of gravity of the second portion and a center of the fixing portion by a mass of the second portion, wherein a first number of first opening portions are formed in a region corresponding to the first portion of the mass body, on the first surface of the substrate, wherein a second number of second opening portions are formed in a region corresponding to the first portion of the mass body, on the second surface of the substrate, wherein the first opening portion and the second opening portion are connected to each other to form a plurality of first through portions in the substrate, and wherein the first number is greater than the second number.