The invention provides a magnifier for a sewing machine that is mounted on a sewing machine main body and magnifies a view of a front end of a needle which is mounted on a needle bar front end that moves vertically and a vicinity of a cloth presser.The magnifier includes: a supporting arm part A, at one end of which a lens holding part 2 having a holding unit 4 that detachably holds a lens is provided, and at the other end of which a mounting part 3 for mounting the magnifier on the sewing machine main body is provided; and a lens main body B that is constituted by connected part 6 which is detachable to the lens holding part 2, and a lens part 5 which is formed continuously to the connected part 6. To the lens holding part 2 of the supporting arm part A as well as the lens main body B, a turning control unit 7 is provided which controls a turning angle of the lens main body B in a predetermined range, and the turning control unit 7 controls a turning angle of the lens main body B that is mounted on the lens holding part 2, in a predetermined range.