In an interface apparatus, when a load is applied to a base member and a connector part is pushed onto an external connector, a spring contracts so that an interval between the base member and a holder is reduced. An inclined surface of a coupling member is separated from an inclined surface of the holder so that fixing of the holder by the coupling member is released and the coupling member can move freely inside a hollow section. As a result, the holder and the connector part can move freely in X-Y directions relative to the base member, and a terminal of a connector can be finely adjusted in the X-Y direction, thus being precisely aligned with the external connector.