In this paper，the secant algorithm-a hardware algorithm of the computer to evaluate approximation of the functions at high speed is suggested. First，the definition of the secant algorithm is described and its scheme is discussed. Then，an improvement of the secant algorithm is given，and an economical method of the structure of the initial va1ue table is recom mended. Finally，the application of the secant algorithm to the design of hardware of the computer is discussed.