To suppress degradation of combustibility by appropriately adjusting the internal exhaust-gas recirculation rate for every cylinder group, in an internal combustion engine in which the internal exhaust recirculation rate is adjustable for every cylinder group.

At the time when learning treatments (S180, S230) for amounts of slide correction for right and left banks respectively are executed, internal EGR (exhaust gas recirculation) is executed for a cylinder group in a corresponding bank, but the EGR is stopped for a cylinder group in other banks (S160, S210). Thus, a slide-correction amount unaffected by internal ERR rate in other cylinder groups can be easily detected. By using the slide-correction amount, an appropriate correction can be performed, in which there is reflected a deviation of a slide adjustment in cylinder groups of respective banks from an actual internal EGR rate, attendant upon a tolerance for a shape of three dimensional intake cam used in a shaft slide mechanism and a tolerance for mounting position. Consequently, degradation of combustibility in each cylinder group is appropriately suppressed.