DEVICE, METHOD, AND PROGRAM RECORDING MEDIUM FOR CONTROL OF AIR-FUEL RATIO OF INTERNAL COMBUSTION ENGINE

An air-fuel ratio control device of an internal combustion engine capable of increasing the purification performance of a catalytic device by accurately compensating the effect of dead-times of an exhaust system including the catalytic device and so forth, wherein an exhaust side control unit (7a) sets the dead-time of the exhaust system (E) and the dead-time of an air-fuel ratio operating system comprising an engine.