A control apparatus of electric power steering apparatus that monitors an execution time of each normal processing of a plurality of normal processings, obtained by subdividing a control program of said electric power steering apparatus into the plurality of normal processings for an execution sequence of the control program, by means of an MCU which is provided in said control apparatus, wherein with respect to said each normal processing, execution time thresholds for execution time monitoring are set respectively, and concurrently with respect to each alternative processing to be paired with said each normal processing, execution time thresholds for execution time monitoring are set respectively, wherein said execution time of said normal processing or an execution time of said alternative processing is measured by means of a general-purpose timer built in said MCU and by starting said general-purpose timer at a beginning of said normal processing or said alternative processing, and stopping said general-purpose timer at an end of said normal processing or said alternative processing and concurrently clearing a timer count value to zero and executing a next normal processing or a next alternative processing based on said execution sequence, wherein in a case that an interruption processing as a normal processing or an alternative processing relating to a control of said electric power steering apparatus is performed during execution of said normal processing or said alternative processing, said general-purpose timer is once stopped at a beginning of said interruption processing and concurrently a timer count value immediately before stopping is stored, and then, after going through an interruption based on said interruption processing, said general-purpose timer is restarted and concurrently timer measurement is performed from said stored timer count value, wherein at a time when said execution time measured by said general-purpose timer reaches an execution time threshold of said normal processing, in a case that said normal processing is not terminated yet, it is judged that an execution time abnormality of said normal processing occurs and concurrently said normal processing is regarded as abnormality, in a current period, said normal processing is stopped by performing a timer interruption processing being a software processing performed by said MCU, a check processing of a calculation value of said normal processing is performed, in a case that said calculation value is abnormal, said calculation value is replaced with a default value, after going through a timer interruption based on said general-purpose timer, the next normal processing or the next alternative processing is performed based on the execution sequence, in a next period, said control of said electric power steering apparatus is continued by performing an alternative processing to be paired with said normal processing as a substitute for said normal processing based on the execution sequence of said normal processing, and wherein at a time when said execution time of said alternative processing measured by said general-purpose timer reaches an execution time threshold of said alternative processing, in a case that said alternative processing is not terminated yet, it is judged that an execution time abnormality of said alternative processing occurs, in a current period, said alternative processing is stopped by performing a timer interruption processing being a software processing performed by said MCU, and subsequently said timer interruption processing is terminated as an abnormal termination.