A door lock is provided to release the locking of a door only by pushing or pulling a knob from in and outside of the door. An inside knob has a center portion provided with a locking button(15) inside a door(100). An inner fixture part is installed inside the door to support the inside knob such that the inside knob moves back and forth. An outside knob is positioned outside the door, and has a center portion provided with a key bundle to release the locking of the door(100). An outer fixture part is provided inside the door(100) to support the outside knob such that the outside knob moves back and forth. A hook member comes moves through a hole formed in a gatepost according to the movement of the inside knob and the outside knob to maintain the close state of the door. A manipulation member(60) moves the hook member right or left when the inside knob or the outside knob(30) moves forward or backward. A guide member(70) is installed inside the door to guide the movement of the hook member.
