To provide a contour extraction apparatus which can perform much more quickly the contour division when required while reducing the cost for computing. In contour extraction unit 32: a plurality of nodes are located on a periphery of the target object by the node locator 32A; the contour, which is formed by connecting nodes at a predetermined connection order, is deformed by the contour deformation unit 32B; an internode distance about all combination of nodes excepting the inter node distance between adjacent nodes is computed by the internode distance calculator 32C; it is checked by the connection creator 32D whether or not the combination of nodes whose internode distance is below a first threshold value exists, a connection line to divide the contour is created, the connection line connects one of nodes in the combination with the node adjacent to the other node in the combination, and the node adjacent to the other node is the node being positioning upstream or downstream in the predetermined connection order with respect to the other node.
