A data division unit divides N components of N-dimensional vector signals to upper bit signals and lower bit signals. A vertex data read-out unit obtains output signals of a unit solid or unit hypersolid corresponding to a combination of the upper bit signals of the N components from a plurality of multi-dimensional LUT units used to divisionally store output signals corresponding to vertices of unit solids or unit hypersolids that configure a lookup table in eight-vertex units. An interpolation computing unit makes interpolation computations of output signals for N-dimensional vector signals based on the obtained output signals and the lower bit signals of the N components.