To provide a lock device for door capable of lighting the inside of a room and the outside of the room at specified luminance to allow a person to easily move to a specific indoor position at night when indoor luminance is not sufficient.

The lock device for door comprises a luminance sensor installed on an inner plate 12 of a door for detecting the indoor luminance, an infrared detection sensor 26 installed on an outer plate 10 for detecting an infrared ray emitted from a human body, a microprocessor comparing a luminance detection signal detected by the luminance sensor with reference luminance data and outputting an lighting control signal when the luminance is not sufficient to cause a light emitting diode 21 built in an inner handle 18 or an outer handle 14 to emit light, a key board 28 for inputting a password and a sound outputting means 29 outputting a melody allowing the confirmation of the state of the lock. The inner handle and the outer handle are formed of transparent or translucent high strength synthetic resins to allow the light of the light emitting diode to permeate.