Function generator is widely used in laboratory especially in electrical and electronics related laboratory. It is use to generate different types of signal wave according to a given function. This paper will discuss about the design of a very low-cost computer-aided function generator. In this system we have to write a function or draw a wave in the computer screen and then the computer software will convert it into a coded signal. After that the computer send this coded signal to the function generator device through USB-port wire as input. Then the function generator device will generate the wave signal according to the input signal sent by the computer and the required wave signal will appear as output of the function generator.