An EGR control device for an internal combustion engine provided with an EGR passage through which an exhaust passage and an intake passage of the internal combustion engine communicate with each other, and with an EGR control valve across which the EGR passage extends and which controls a flow rate of EGR gas flowing from the exhaust passage to the intake passage, comprising: operational state quantity acquisition means that acquires an operational state quantity of the engine; target EGR ratio determination means that determines, on the basis of the detected operational state quantity, a target value of an EGR ratio, namely, a ratio of a flow rate of EGR gas sucked by the engine to a flow rate of gas sucked by the engine, as a target EGR ratio; target air flow rate determination means that determines, on the basis of the detected operational state quantity, a target value of a flow rate of air sucked by the engine, as a target air flow rate; actual EGR ratio acquisition means that acquires a true EGR ratio on the basis of the detected operational state quantity, as an actual EGR ratio; actual air flow rate acquisition means that acquires, on the basis of the detected operational state quantity, an actual flow rate of air sucked by the engine, as an actual air flow rate; and characterised by: EGR ratio control means - for which a target converted EGR ratio is defined as a value corresponding to a ratio of the target EGR ratio to a target excessiveness ratio tgt as being a ratio of the target air flow rate to a command injection amount, and for which an actual converted EGR ratio is defined as a value corresponding to a ratio of the actual EGR ratio to an actual excessiveness ratio λ, as being a ratio of the actual air flow rate to the command injection amount, wherein the EGR ratio control means - controls the actual EGR ratio by controlling an opening of the EGR control valve in accordance with the actual converted EGR ratio and the target converted EGR ratio. operational state quantity acquisition means that acquires an operational state quantity of the engine; target EGR ratio determination means that determines, on the basis of the detected operational state quantity, a target value of an EGR ratio, namely, a ratio of a flow rate of EGR gas sucked by the engine to a flow rate of gas sucked by the engine, as a target EGR ratio; target air flow rate determination means that determines, on the basis of the detected operational state quantity, a target value of a flow rate of air sucked by the engine, as a target air flow rate; actual EGR ratio acquisition means that acquires a true EGR ratio on the basis of the detected operational state quantity, as an actual EGR ratio; actual air flow rate acquisition means that acquires, on the basis of the detected operational state quantity, an actual flow rate of air sucked by the engine, as an actual air flow rate; and characterised by: EGR ratio control means - for which a target converted EGR ratio is defined as a value corresponding to a ratio of the target EGR ratio to a target excessiveness ratio tgt as being a ratio of the target air flow rate to a command injection amount, and for which an actual converted EGR ratio is defined as a value corresponding to a ratio of the actual EGR ratio to an actual excessiveness ratio λ, as being a ratio of the actual air flow rate to the command injection amount, wherein the EGR ratio control means - controls the actual EGR ratio by controlling an opening of the EGR control valve in accordance with the actual converted EGR ratio and the target converted EGR ratio. EGR ratio control means - for which a target converted EGR ratio is defined as a value corresponding to a ratio of the target EGR ratio to a target excessiveness ratio tgt as being a ratio of the target air flow rate to a command injection amount, and for which an actual converted EGR ratio is defined as a value corresponding to a ratio of the actual EGR ratio to an actual excessiveness ratio λ, as being a ratio of the actual air flow rate to the command injection amount, wherein the EGR ratio control means - controls the actual EGR ratio by controlling an opening of the EGR control valve in accordance with the actual converted EGR ratio and the target converted EGR ratio. - for which a target converted EGR ratio is defined as a value corresponding to a ratio of the target EGR ratio to a target excessiveness ratio tgt as being a ratio of the target air flow rate to a command injection amount, and for which an actual converted EGR ratio is defined as a value corresponding to a ratio of the actual EGR ratio to an actual excessiveness ratio λ, as being a ratio of the actual air flow rate to the command injection amount, wherein the EGR ratio control means - controls the actual EGR ratio by controlling an opening of the EGR control valve in accordance with the actual converted EGR ratio and the target converted EGR ratio.