The object is to provide a technology that can prevent a spring electrode from being dissolved and broken upon a short circuit in a semiconductor chip. A spring electrode includes a main body. The main body is a tubular conductor, and varies in diameter in a longitudinal direction so that a side surface has bellows. Since the main body of the spring electrode does not include an edge portion, the local concentration of a short-circuit current that flows through the spring electrode upon a short circuit in a semiconductor chip can be reduced. This can prevent the spring electrode from being dissolved and broken.