This paper syggests the power vector and the vector power series. The vector power series is a "Combinatorial Vector Number" which is composed of a real number and a certain vector. Combinatorial rector variable and its functions have an important meaning. They have the fundamental operations of arithemetic too. From the theoretical analysis of functions for a combinatorial vector variable we would would know its function has the derivatives. the necessary and sufficient conditions. These conditions make up the charaders of "Hyperbolic equation" and its integralions.