A control device for an internal combustion engine with an EGR device which recirculates a part of exhaust gas of the internal combustion engine to an intake channel via an exhaust gas recirculation channel, the internal combustion engine being configured to control an EGR amount by adjusting an opening degree of an EGR valve disposed in the EGR channel, the control device comprising: a first temperature detection unit disposed in the intake channel and on an upstream side of a merging part at which the intake channel merges with the EGR channel; a second temperature detection unit disposed in the intake channel and on a downstream side of the merging part; a third temperature detection unit disposed in the EGR channel and between the EGR valve and the merging part; a pressure detection unit disposed in the intake channel and on the downstream side of the merging part; an EGR-valve basic opening degree calculation unit configured to calculate a basic opening degree (Db) of the EGR valve on the basis of an operation state (Ne, Qf) of the internal combustion engine; an estimate-value calculation unit (44,56) configured to calculate an estimate value of at least one of an air-excess ratio (As) in a combustion chamber of the internal combustion engine or an intake oxygen concentration on the basis of a fuel-injection amount (Qf) of the internal combustion engine, a rotation speed (Ne) of the internal combustion engine, and detection values obtained by the first temperature detection unit, the second temperature detection unit, the third temperature detection unit, and the pressure detection unit; a target-value calculation unit (46,48) configured to calculate a target value of at least one of the air-excess ratio (At) or the intake oxygen concentration (RO2t) on the basis of the operation state of the internal combustion engine; a correction-factor calculation unit configured to calculate a correction factor (k) for the basic opening degree of the EGR valve on the basis of the estimate value and the target value; an opening-degree command value calculation unit configured to calculate an opening-degree command value for the EGR valve on the basis of the basic opening degree (Db) and the correction factor (k); and a control unit configured to control the opening degree of the EGR valve on the basis of the opening-degree command value, characterized by further comprising a load detection unit configured to detect a load of the internal combustion engine, wherein the correction-factor calculation unit is configured to calculate the correction factor on the basis of the estimate value and the target value of the air-excess ratio if the load detected by the load detection unit is at least a predetermined value, and to calculate the correction factor on the basis of the estimate value and the target value of the intake oxygen concentration if the load detected by the load detection unit is less than the predetermined value. a first temperature detection unit disposed in the intake channel and on an upstream side of a merging part at which the intake channel merges with the EGR channel; a second temperature detection unit disposed in the intake channel and on a downstream side of the merging part; a third temperature detection unit disposed in the EGR channel and between the EGR valve and the merging part; a pressure detection unit disposed in the intake channel and on the downstream side of the merging part; an EGR-valve basic opening degree calculation unit configured to calculate a basic opening degree (Db) of the EGR valve on the basis of an operation state (Ne, Qf) of the internal combustion engine; an estimate-value calculation unit (44,56) configured to calculate an estimate value of at least one of an air-excess ratio (As) in a combustion chamber of the internal combustion engine or an intake oxygen concentration on the basis of a fuel-injection amount (Qf) of the internal combustion engine, a rotation speed (Ne) of the internal combustion engine, and detection values obtained by the first temperature detection unit, the second temperature detection unit, the third temperature detection unit, and the pressure detection unit; a target-value calculation unit (46,48) configured to calculate a target value of at least one of the air-excess ratio (At) or the intake oxygen concentration (RO2t) on the basis of the operation state of the internal combustion engine; a correction-factor calculation unit configured to calculate a correction factor (k) for the basic opening degree of the EGR valve on the basis of the estimate value and the target value; an opening-degree command value calculation unit configured to calculate an opening-degree command value for the EGR valve on the basis of the basic opening degree (Db) and the correction factor (k); and a control unit configured to control the opening degree of the EGR valve on the basis of the opening-degree command value, characterized by further comprising a load detection unit configured to detect a load of the internal combustion engine, wherein the correction-factor calculation unit is configured to calculate the correction factor on the basis of the estimate value and the target value of the air-excess ratio if the load detected by the load detection unit is at least a predetermined value, and to calculate the correction factor on the basis of the estimate value and the target value of the intake oxygen concentration if the load detected by the load detection unit is less than the predetermined value.