PURPOSE: To shorten processing time for generating an contour line by properly using an incorporated memory and the exterior memory in accordance with the size of a character and graphic to be generated.

CONSTITUTION: A character and graphic generating circuit 4 temporarily generates the contour line in the incorporated memory 8 by the size of the character and graphic to be generated or generates it in the exterior memory 3 as it is. Thus, the access time to the exterior memory 3 is reduced at the time generating the contour line in the incorporated memory 8 so that the character and graphic of an average size with high frequency are generated at high speed. When the contour line is generated in the exterior memory 3, the character and graphic of the large size are generated. Here, a straight line generating circuit 7 permits a means calculating a parameter by the start point coordinate and end point coordinate of the straight line and the means plotting the straight line on the memory based on the parameter to asynchronously execute an operation. Thus, a straight line generation processing is made into a pipeline so that the straight line constituting the contour line is generated at high speed.