A motor control unit comprising: a motor control signal output unit configured to output a motor control signal; a drive circuit configured to supply a driving current to a motor based on the motor control signal; and an abnormality detection unit configured to detect a current-carrying failure in an electric power supply path to the motor based on a voltage parameter corresponding to a voltage that is applied to the motor, characterized in that the abnormality detection unit is configured to determine whether a first determination condition is satisfied, the first determination condition including a condition that an actual current value that indicates an electric current actually supplied to the motor is smaller than or equal to a predetermined current value that indicates a non-current carrying state and the voltage parameter is higher than or equal to an upper limit of a predetermined range corresponding to the predetermined current value, and the abnormality detection unit is configured to determine whether a second determination condition is satisfied, the second determination condition including a condition that the actual current value is smaller than or equal to the predetermined current value and the voltage parameter is lower than or equal to a lower limit of the predetermined range, the abnormality detection unit is configured to measure a first duration that is a duration of time that a state where the first determination condition is satisfied continues, and a second duration that is a duration of time that a state where the second determination condition is satisfied continues, the abnormality detection unit comprises means configured to perform a reference period setting, and the abnormality detection unit is further configured to determine that a current-carrying failure has occurred when the first duration or the second duration exceeds a predetermined reference period that is set based on a rotation period of the motor when the motor is rotating at such a high speed that the voltage parameter falls outside the predetermined range due to an influence of inductive voltage. a motor control signal output unit configured to output a motor control signal; a drive circuit configured to supply a driving current to a motor based on the motor control signal; and an abnormality detection unit configured to detect a current-carrying failure in an electric power supply path to the motor based on a voltage parameter corresponding to a voltage that is applied to the motor, characterized in that the abnormality detection unit is configured to determine whether a first determination condition is satisfied, the first determination condition including a condition that an actual current value that indicates an electric current actually supplied to the motor is smaller than or equal to a predetermined current value that indicates a non-current carrying state and the voltage parameter is higher than or equal to an upper limit of a predetermined range corresponding to the predetermined current value, and the abnormality detection unit is configured to determine whether a second determination condition is satisfied, the second determination condition including a condition that the actual current value is smaller than or equal to the predetermined current value and the voltage parameter is lower than or equal to a lower limit of the predetermined range, the abnormality detection unit is configured to measure a first duration that is a duration of time that a state where the first determination condition is satisfied continues, and a second duration that is a duration of time that a state where the second determination condition is satisfied continues, the abnormality detection unit comprises means configured to perform a reference period setting, and the abnormality detection unit is further configured to determine that a current-carrying failure has occurred when the first duration or the second duration exceeds a predetermined reference period that is set based on a rotation period of the motor when the motor is rotating at such a high speed that the voltage parameter falls outside the predetermined range due to an influence of inductive voltage.