VEHICLE DOOR SYSTEM COMPRISING DOOR LATCH DEVICE

A door latch device for vehicle has a detection switch for enabling detection of a door-opening operation of an operation handle when a locking/unlocking mechanism is in an unlatch position. For this purpose, the door latch device for vehicle includes a meshing mechanism, an open link 20, a smart lever 26, and a smart lever detection switch 27. The meshing mechanism is meshable with a striker when a door is closed. The open link 20 is configured to be movable to an unlock position where an opening operation of an operation handle provided at the door is enabled and where meshing of the meshing mechanism is releasable, and to be movable to a lock position where the opening operation of the operation handle provided at the door is disabled and where meshing of the meshing mechanism is unreleasable. The smart lever 26 is configured to be operable in linking with the opening operation of the operation handle when the open link 20 is in the unlock position, and to be inoperable in linking with the opening operation of the operation handle when the open link 20 is in the lock position. The smart lever detection switch 27 is configured to be detectable an operation of the smart lever 26.