To provide a locking device of a door for an elevator capable of preventing generation of harsh noise when a cage ascends/descends.

A locking metal fitting 2 is fitted to one side part of an opening and closing door 1 of the elevator, a latch 4 hooked on the locking metal fitting 2 to put the opening and closing door 1 in the closed state is rotatably mounted on a rail 3 for the opening and closing door 1, and with the cage 11 placed on the rear face of the opening and closing door 1, magnets 7, 15 are respectively mounted on the latch 4 and a rail 13 for a front door 12 of the cage 11 with the N-poles opposite to each other, whereby when the cage 11 reaches the rear face of the opening and closing door 1, the latch 4 is turned without contacting the cage 11 by repulsive force working between the magnets 7, 15 to be removed from the lock metal fitting 2 so that locking of the opening and closing door 1 is released not to generate contact noise with the latch 4 when the cage 11 ascends/descends.