This paper introduces QC2AS which is a newly designed and developed computer algebra system for symbolic quantum chemical computations. With the rapid advancement of computer, the concern with high-level model chemistry has been growing. To handle such models, it is necessary to manipulate huge algebraic formulas. QC2AS has been designed to handle algebraic formulas appeared in quantum chemistry and it provides an access to our computer algebraic techniques without knowing the background theories. In this paper, we introduce its features and the architecture with some illustrative examples. This is the first report about the development of QC2AS.