To provide a door opening/closing mechanism which avoids a collision hazard caused at the time of opening a door, in the case where the thickness of the door is increased.

There is provided a door opening/closing mechanism which includes the door 1 and a chassis 4. The door 1 has opening stopper rails 2 and a pair of holes 11. Each opening stopper rail 2 having a circular-curved guide hole 3 formed in a central portion thereof, has its one end attached to an upper portion of a side surface of the door 1 in one body. Each hole 11 is formed in a lower portion of the side surface, for inserting a hinge pin 6 therein. The chassis 4 has a pair of rail attaching portions 41 and a pair of long guide holes 8. Each rail attaching portion 41 is arranged at an upper portion of an opening surface of the chassis, and the other end of the opening stopper rail 2 is attached to the rail attaching portion 41 by using a guide pin 5. Each guide hole 8 is formed in a lower portion of the opening surface for slidingly coupling the door 1 with the chassis 4 by using the hole 11 and the hinge pin 6.