A door locking device is provided to implement opening and locking of a door at the same time by forming one-way engaging structure through a release lever between an inside lever and a lock lever and moving a dead bolt and a latch bolt backward through switching of an internal handle at the same time. A door locking device comprises: a case(10) with a latch bolt hole(11) and a dead bolt hole(12); a latch bolt(20) being inserted into the latch bolt hole and moving forward and backward by operating with an inner lever(40) or an outer lever(50); and a dead bolt(30) being inserted into the dead bolt hole and moving forward and backward by operating with a lock lever(60) switched with a thumb turn lever or a key set. The inner lever and outer lever have independent link structure by forming an operating terminal(32). A spring(21) is formed in the latch bolt.
