The Depth - First Picture Expression (DF - Expression) is an effective data compression technique for binary images. When we apply it to a real eqip-ment, we need a practical encoding/decoding scheme which should be fast and simple in the operation. In the present paper, we study two types of coding algorithm, one is the top-down and the other is the bottom-up methods. Those algorithms are put into two C programs to compare the speed. We also designed an encoding/decoding hardware device, and built it on a breadboad which is linked to a workstation. As a result, it became certain that the hardware encoder/decoder can achieve a 50-100 times faster operation than the C programs run on a 4 MIPS workstation.