PURPOSE: To prepare only the dot character pattern of the maximum degree in case the character has more than two types of degree and then to secure an automatic selection for the matrix of the prescribed number to be deleted from the above mentioned character pattern.

CONSTITUTION: The original dot character pattern is generated 5, and the dot state in l0l2 adjacent to optional lines l1 and l1 is recorded 6. Then dot B in l2 as well as dot A in l0 adjacent to optional dots P and P in l1 are selected from the memorized dot state, and at the same time the adaptability for deletion of dot P is defined via logic circuit network 7 which is prescribed based on P, A and B. The maximum continuous number m in the direction of l1 of the deletion unable dot in l1 is counted and memorized 8, and the deletion lines of the preseribed number are selected and deleted 10 in sequence from the line of the minimum m to the lines of larger m in order to decrease the degree of the dot character pattern. In this constitution, the form of the character pattern is not impaired so much through the reduction conversion, and the high-quality reduced character can be generated in a high speed just by adding the hardware of the degree reduction/conversion part.