To provide a locking device for an inward-opening window, capable of positively holding a lock state.

This locking device for an inward-opening window locks a window sash 5 into a closed position or releases lock by rotating a handle part 21 of a latch bar 19 to engage a latch 22 into a latch hole 11 or detach it. The handle part 21 of the latch bar 19 is separated from the other part 23 and pivotally connected in a tiltable manner between a first position linearly extended from the other part 23 and a second position tilted in a separating direction from the inner surface side of the sash 5. The handle part 21 is energized into the first position by a spring 25, and the handle part 21 is provided with an engaging part 26. An engaged part 27 engaged with the engaging part 26 when the handle part 21 is in the first position, so as to impede the rotation of the handle part 21 in a lock release direction is provided on the window sash 5 side opposed to the engaging part 26.