Abstract: Disclosed are a weight memory device capable of supporting artificial neural network operation and a weight memory system using the same. A weight memory device according to an embodiment of the present invention includes: an input terminal; a common output terminal; and charge storage disposed between the input terminal and the common output terminal, and configured to store charge. In this case, the capacitance between the input terminal and the common output terminal is determined based on the amount of charge stored in the charge storage, and is quantified based on given data to be stored in the weight memory device.