To provide a display controller which can be used as a pseudo display system without restrictions on operation conditions.

Inclination of a head mount display device 5 is detected, and a correction angle having a polarity opposite to that of the angle of this inclination is given to a picture generator to cancel the inclination, thereby keeping the horizontal direction of a pseudo picture. In this case, invisible light emitters 10a to 10h as the reference are built on the screen side and an infrared camera 7a is built on the observer side as a measuring system so that an inclination measuring system may not be added in accordance with conversion to a multi- screen system.