A control device of a multi-cylinder engine is provided. The control device includes an auxiliary component and a valve stopping device having a locking mechanism for stopping an operation of at least one of intake and exhaust valves of a specific cylinder of the multi-cylinder engine according to an engine operating state. The control device includes an angular speed variation detecting device for detecting an angular speed variation of a crankshaft, an auxiliary component control device for controlling a drive load of the auxiliary component. In an all-cylinder operation, when an engine load is lower than a predetermined value and the detected angular speed variation exceeds a predetermined threshold, the auxiliary component control device performs an auxiliary component drive load increase control in which the drive load of the auxiliary component is increased to reduce the angular speed variation to be lower than the predetermined threshold.