In order to reuse configuration information in a dynamic reconfiguration arithmetic circuit, data lines, address lines, a mask register and the like are required as hardware resources for rewriting only configuration information of dynamic reconfiguration arithmetic cells needed to be changed. However, this results in an increase in area of the arithmetic circuit. According to the present invention, a shift register is the only hardware resource in the dynamic reconfiguration arithmetic block for changing the configuration information. The shift register is structured by connecting in series storage units corresponding one-to-one with each arithmetic cell. An output from the end terminal of the shift register and an output of the configuration information storage unit are input to the configuration information selector, and an output of the configuration information selector is connected to the front of the shift register. The cell address counter counts up from 0 and increments one at a time. Only when the count value is equal to a cell address for configuration change, the configuration information selector selects the configuration information storage unit; otherwise, the configuration information selector reuses configuration information output from the end terminal of the shift register.