A method for determining whether a component part of mechanical products can be removed is necessary for design verification of the products. This problem has been solved by only considering contact states of component parts so far, though that is insufficient. In this paper, a component part is determined as removable when it can be moved to infinity with one translation without coiliding with other component parts. It is shown that a set of all directions along which a component part prohibited the other one from moving to infinity becomes a polyhedral convex cone when both component parts are given as convex polyhedrons. An algorithm for verifying the removability of a component part is developed. The algorithm takes O(N3ν) time on the average, where Nυ is the number of vertices of a geometric model of mechanical product. The effectiveness of the developed algorithm is demonstrated by examples.