To provide a lock effective to prevent the generation of crime by, for example, protecting a lattice window from removal thereof from outside.

This lock is formed of two presser members 13 and 13 for pinching a back surface part of the lattice window 1 and a front part of a window sash 7 and a fastening screw 14 for fastening the two presser members 13 and 13 from inside the window sash 7 at positions displaced from the shaft center of the presser member 13 in the condition wherein the two presser members are arranged opposite to each other.