A method of manufacturing a Fabry-Perot interference filter comprising: a forming step of forming a first mirror layer having a plurality of first mirror portions each of which is expected to function as a fixed mirror, a sacrificial layer having a plurality of portions expected to be removed, and a second mirror layer having a plurality of second mirror portions each of which is expected to function as a movable mirror, on a first main surface of a wafer which includes parts corresponding to a plurality of two-dimensionally arranged substrates and is expected to be cut into the plurality of substrates along each of a plurality of lines, such that one first mirror portion, one portion expected to be removed, and one second mirror portion are disposed in this order from one substrate side; a removing step of simultaneously removing the plurality of two-dimensionally arranged portions expected to be removed from the sacrificial layer through etching after the forming step; a cutting step of cutting the wafer into the plurality of substrates along each of the plurality of lines after the removing step; characterized in that: wherein in the forming step, a first thinned region, in which at least one of the first mirror layer, the sacrificial layer, and the second mirror layer is partially thinned along each of the plurality of lines, is formed; and wherein in the forming step, after a part along each of the plurality of lines in the sacrificial layer formed on the first mirror layer is thinned: side surfaces of the sacrificial layer facing each other along each of the plurality of lines are covered with the second mirror layer by forming the second mirror layer on the sacrificial layer; for each part corresponding to each of the plurality of substrates a gap is formed in the sacrificial layer and in the second mirror layer on the inside of the side surfaces of the sacrificial layer; and a terminal (15, 16) is formed in the gap for each part corresponding to each of the plurality of substrates. a forming step of forming a first mirror layer having a plurality of first mirror portions each of which is expected to function as a fixed mirror, a sacrificial layer having a plurality of portions expected to be removed, and a second mirror layer having a plurality of second mirror portions each of which is expected to function as a movable mirror, on a first main surface of a wafer which includes parts corresponding to a plurality of two-dimensionally arranged substrates and is expected to be cut into the plurality of substrates along each of a plurality of lines, such that one first mirror portion, one portion expected to be removed, and one second mirror portion are disposed in this order from one substrate side; a removing step of simultaneously removing the plurality of two-dimensionally arranged portions expected to be removed from the sacrificial layer through etching after the forming step; a cutting step of cutting the wafer into the plurality of substrates along each of the plurality of lines after the removing step; characterized in that: wherein in the forming step, a first thinned region, in which at least one of the first mirror layer, the sacrificial layer, and the second mirror layer is partially thinned along each of the plurality of lines, is formed; and wherein in the forming step, after a part along each of the plurality of lines in the sacrificial layer formed on the first mirror layer is thinned: side surfaces of the sacrificial layer facing each other along each of the plurality of lines are covered with the second mirror layer by forming the second mirror layer on the sacrificial layer; for each part corresponding to each of the plurality of substrates a gap is formed in the sacrificial layer and in the second mirror layer on the inside of the side surfaces of the sacrificial layer; and a terminal (15, 16) is formed in the gap for each part corresponding to each of the plurality of substrates. wherein in the forming step, a first thinned region, in which at least one of the first mirror layer, the sacrificial layer, and the second mirror layer is partially thinned along each of the plurality of lines, is formed; and wherein in the forming step, after a part along each of the plurality of lines in the sacrificial layer formed on the first mirror layer is thinned: side surfaces of the sacrificial layer facing each other along each of the plurality of lines are covered with the second mirror layer by forming the second mirror layer on the sacrificial layer; for each part corresponding to each of the plurality of substrates a gap is formed in the sacrificial layer and in the second mirror layer on the inside of the side surfaces of the sacrificial layer; and a terminal (15, 16) is formed in the gap for each part corresponding to each of the plurality of substrates. side surfaces of the sacrificial layer facing each other along each of the plurality of lines are covered with the second mirror layer by forming the second mirror layer on the sacrificial layer; for each part corresponding to each of the plurality of substrates a gap is formed in the sacrificial layer and in the second mirror layer on the inside of the side surfaces of the sacrificial layer; and a terminal (15, 16) is formed in the gap for each part corresponding to each of the plurality of substrates.