1. A collision determination device comprising: a computer comprising a collision determination program executed by the computer to program the collision determination device to function as: a shape data storage unit that stores both voxel model data representing a shape of a first object by a voxel model and boundary representation model data representing a shape of a second object by a boundary representation model which provides representations with a collection of shaped and oriented boundary elements and an adjacent phase structure between those elements, the voxel model being defined by a coordinate system fixed to the first object, the boundary representation model being defined by a coordinate system fixed to the second object; a target cell designation unit that designates, among cells constituting the voxel model, a target cell to determine a collision; a determination test point generation unit that uses at least the voxel model data to generate, as a determination test point that is exclusively used for determining a collision for the target cell, a test point located at a corner of a sub-cubic region obtained by recursively octo-dividing an occupied cubic region of a distal end cell; a spatial curve creation unit that creates a spatial curve as a trajectory curve of each of the determination test points by applying rigid body movement data representing combined rotational movement as a function of time and translational movement as a function of time, provided to the collision determination device as input to the spatial curve creation unit, indicating a relative rigid body motion of the first object in the voxel model with respect to the second object in the boundary representation model to each of the determination test points; a curve intersecting determination unit that uses at least the boundary representation model data to determine whether or not each boundary element of the boundary representation model is intersecting the spatial curve; a distance computation unit that computes a closest distance from the spatial curve to a boundary surface of the boundary representation model, when a determination result provided by the curve intersecting determination unit shows that the spatial curve intersects no boundary element; and a collision determination unit that determines a possibility of collision between both objects based on both the determination result provided by the curve intersecting determination unit and a computation result provided by the distance computation unit.