A MEMS device, including: a substrate (101) having a first principal plane and a second principal plane opposite to the first principal plane; a through hole (110) formed in the substrate (101); and a vibrating film (105) formed over the first principal plane so as to cover the through hole (110). The first principal plane and the second principal plane are both a (110) crystal face; and the through hole (110) has a substantially rhombic shape on the second principal plane.
