In the last few years, LSI design using C++ language has been the focus of attention. However, almost no library written in C++ is opened to the public. Therefore, development of a library written in C++ is necessary in order to design LSI efficiently. C++ language for LSI design needs many types as int4, int8, etc., which correspond to the bit width of ports, signals, buses, etc. of hardware. If we use C++ classes to develop the library for LSI, we need as many classes as types. In order to avoid this, we decided to use C++ templates to develop the library. In this paper, we describe a C++ template library for LSI design and application to the LSI design education in the Department of Electrical and Digital Systems Engineering.