To provide a door controller which can prevent a door from coming into collision with a person who is on the opposite side to the door when the door is opened.

A person A who wants to enter a room makes an outside card reader 121 read card information of an ID card, and an authentication part 210 performs authentication processing based on the information read by the outside card reader 121. When the person A has been authenticated by the authentication part 210, the camera control part 220 obtains camera images from an interior camera 142, and a monitor control part 230 displays the camera images of the interior on an outside monitor 131. An electric lock control part 250 unlocks an electric lock 112 after the camera images have been displayed, and the person A confirms the state of the interior by the outside monitor 131, and opens the door 111.