An electric power steering system comprising: an electric motor including a first coil and a second coil; a first driving circuit configured to supply electric power to the first coil; a second driving circuit configured to supply electric power to the second coil; a first current detector configured to detect a current flowing through the first coil; a second current detector configured to detect a current flowing through the second coil; a first corrector configured to apply offset correction to a first detected current detected by the first current detector, based on a first correction value; a second corrector configured to apply offset correction to a second detected current detected by the second current detector, based on a second correction value; a command value calculator configured to calculate a basic current command value of the electric motor; a distributor configured to divide the basic current command value into a first current command value and a second current command value; a first controller configured to control the first driving circuit, based on the first detected current after the offset correction by the first corrector, and the first current command value; a second controller configured to control the second driving circuit, based on the second detected current after the offset correction by the second corrector, and the second current command value; characterized by a third corrector configured to correct the first correction value and the second correction value, wherein the third corrector is configured to i) correct the second correction value while the distributor is controlled such that 100% of the basic current command value is the first current command value, and 0% of the basic current command value is the second current command value, and ii) correct the first correction value while the distributor is controlled such that 100% of the basic current command value is the second current command value, and 0% of the basic current command value is the first current command value. an electric motor including a first coil and a second coil; a first driving circuit configured to supply electric power to the first coil; a second driving circuit configured to supply electric power to the second coil; a first current detector configured to detect a current flowing through the first coil; a second current detector configured to detect a current flowing through the second coil; a first corrector configured to apply offset correction to a first detected current detected by the first current detector, based on a first correction value; a second corrector configured to apply offset correction to a second detected current detected by the second current detector, based on a second correction value; a command value calculator configured to calculate a basic current command value of the electric motor; a distributor configured to divide the basic current command value into a first current command value and a second current command value; a first controller configured to control the first driving circuit, based on the first detected current after the offset correction by the first corrector, and the first current command value; a second controller configured to control the second driving circuit, based on the second detected current after the offset correction by the second corrector, and the second current command value; characterized by a third corrector configured to correct the first correction value and the second correction value, wherein the third corrector is configured to i) correct the second correction value while the distributor is controlled such that 100% of the basic current command value is the first current command value, and 0% of the basic current command value is the second current command value, and ii) correct the first correction value while the distributor is controlled such that 100% of the basic current command value is the second current command value, and 0% of the basic current command value is the first current command value. i) correct the second correction value while the distributor is controlled such that 100% of the basic current command value is the first current command value, and 0% of the basic current command value is the second current command value, and ii) correct the first correction value while the distributor is controlled such that 100% of the basic current command value is the second current command value, and 0% of the basic current command value is the first current command value.