Estimation sections which have beforehand learned a relationship between known connection data pertaining to connection design and unknown connection data pertaining to connection design for the known connection data estimate the unknown connection data for the known connection data in accordance wit an input of the known connection data, on the basis of the result of learning. The respective estimation sections are formed from a multilayer feedforward neural network in which layers constituted of a plurality of neurons are coupled together in a direction in which the layer runs from an input layer to an output layer by way of an intermediate layer.