PURPOSE:To obtain binarized data with a simple configuration by binarizing a video signal by a comparator and converting the output of the comparator into sampling data by a flip-flop circuit. CONSTITUTION:The comparator 2 compares the video signal Va with threshold value Vth from a threshold value generating circuit 1. A flip-flop circuit 3 latches the output Vb of the comparator 2 each time a clock signal CLK is inputted. A synchronous separating circuit 5 extracts a vertical and a horizontal synchronizing signal from the signal Va. An acknowledgement signal generating circuit 6 generates write acknowledgement signals VEN and HEN on the basis of those signals. A one-bit memory 4 stores the output of the flip-flop circuit 3 when a write acknowledgement signal is outputted from an AND circuit 7. Thus, the binarized data are stored in a memory 4 and character patterns, etc., are recognized with the data.