To obtain an image processing device to compute the values of the center of gravity of an input image inexpensively at a high speed, by reading parameters computed by a gate array and performing necessary calculations at a calculating means.

Each parameter of the numerator and denominator of a specific expression necessary for computing the values of the center of gravity is calculated by a gate array 30 in a simple constitution. Then, a computer 70 reads values stored in memory 60, performs the division of the parameters of the numerator and denominator and computes the values Ha and Vc of the center of gravity in the traverse direction (h) and vertical direction (v) of an input image. In this way, the parameters calculated from the values of the center of gravity are computed by the gate array 30 as fetching an image signal 101 from an image sensor 10 in synchronization with the horizontal synchronizing signal 104 and vertical synchronizing signal 103 of the image signal 101 and the clock signal 105 of a clock generator 23, and the computer 70 performs only the division of the parameters. Therefore, it is possible to obtain the effects that the calculation period of the values of the center of gravity becomes approximately equal to image capturing time from the image sensor 10. In addition, as the gate array 30 constitutes an arithmetic circuit for parameters, it is possible to obtain the effects that a device becomes compact, and that a system can be inexpensively constituted and easily extended.