PURPOSE: To make picture reading consecutively by storing a picture signal inputted thereafter to a picture storage device without coding when an idle capacity of a line buffer reaches a specified value or below.

CONSTITUTION: When a picture signal is extracted from a line buffer in the unit of one line and stored to a picture storage device 8 and a stored line number of the line buffer is smaller than a prescribed value A, while the picture signal of one line is coded and compressed by a coding/decoding section 7, the signal is stored to the picture storage device 8, and when the storage line number of the line buffer reaches the prescribed value A or over, while the picture signal of one line is not coded, the signal is stored to the picture storage device 8. In general, the data transmission time from the line buffer to the picture storage device 8 is enough to overflow the line buffer because the time is shorter than the period time of the read line synchronizing signal LS and the picture read operation of the scanner 4 is implemented continuously.