To provide a door having a function to prevent picking, cam-feed unlocking or the like.

A door with a lock 1 is provided at an entrance of a residence. A mirror 5 is installed in front of the door 1 for reflecting at least a part of the upper half of the body of a man turning a lock 4. The figure of the man is surely reflected in the mirror 5 of the door 1 when unlocking the lock 4, so that, by letting a criminal carrying out picking and the like or a man coming up to the door 1 to carry it out see himself in the mirror 5, it is possible to have him give up or stop such evil deeds. Since the figure of a front side of the criminal doing in the middle of picking is reflected in the mirror 5 of the door 1, the face or the characteristics of the criminal is easy to be witnessed by people passing the road or a hallway which face to the door 1. Also, unlocking the lock 4 of the door 1 or opening the door 1, the resident can get the situation behind her/him by looking through the mirror 5, so that she/he can unlock or open the door after confirming the safe condition where there is not any suspicious person behind herself/himself.