A covered acceleration sensor element includes a support frame portion surrounding a weight portion, a plurality of flexible beam portions for connecting the weight portion to the support frame portion, and piezoresistance elements provided on the beam portions. An upper cover and a lower cover enclosing the periphery of the weight portion together with the support frame portion are joined to the face and back of the support frame portion. The support frame portion is separated by separation grooves into an inner frame and an outer frame. The plurality of inner frame support portions has flexibility. The beam portions are connected to both sides of the weight portion along the second axis and the third axis. The inner frame support portions are connected to both sides of the inner frame in a direction in which they are rotated nearly 45 degrees from the second axis and the third axis.