PURPOSE: To provide a bolt lock device in which a bolt is held at a position where it does not hinder the closing of the door, as far as the door is opened, and which is automatically locked when the door is closed, and as a result, the door is drawn to a door frame so as to eliminate play therebetween.

CONSTITUTION: A part of a trigger 6 for detecting opening and closing of a door D, which is projected from the front end' of the door upon opening, is inserted in a bolt 4 adapted to be turned by a spindle, or a part pivotally attached to the bolt 4, and accordingly, the bolt 4 is stationarily held at the opening position. During closing of the door, the trigger 6 is moved by a door frame F so that the locking is made by the dead weights of the bolt and the other parts. Further, a part of the bolt is formed therein with an inclined surface which cooperates with an inclined part formed in a receiving seat 3 so as to urge the door D to approach the door frame F in its locking condition, thereby it is possible to eliminate play therebetween.