A controlling apparatus for an engine, the engine comprising: a variable geometry turbocharger comprising a turbine disposed in an exhaust path, a compressor disposed in an intake path, and vanes for adjusting a flow rate; a first recirculation system comprising a first adjuster to adjust a flow rate of exhaust gas in a first path, the first path connecting an upstream position of the turbine to a downstream position of the compressor; and a second recirculation system comprising a second adjuster to adjust a flow rate of exhaust gas in a second path, the second path connecting a downstream position of the turbine to an upstream position of the compressor, the controlling apparatus comprising: a calculator configured to calculate a target quantity being the sum of the flow rates of exhaust gas in the first path and second path in response to an operating state of a vehicle; a recirculation controller configured to execute a feedback control of at least one of the first adjuster and the second adjuster on the basis of the target quantity, and to switch between a single use and a combination use, the single use activating one of the first recirculation system and the second recirculation system, the combination use activating both the first recirculation system and the second recirculation system; and a pressure controller configured to execute a feedback control of an intake-system pressure in the downstream position of the compressor through adjustment of an opening of the vanes in response to the operating state, characterized in that when the recirculation controller is switched from the single use to the combination use during the feedback control of the intake-system pressure and the feedback control of one of the first adjuster and the second adjuster is to be performed after the switch, the pressure controller prohibits the feedback control of the intake-system pressure and executes a feedforward control of the intake-system pressure and performs the feedback control of one of the first adjuster and the second adjuster in a predetermined period that begins at a moment when the single use is switched to the combination use. a variable geometry turbocharger comprising a turbine disposed in an exhaust path, a compressor disposed in an intake path, and vanes for adjusting a flow rate; a first recirculation system comprising a first adjuster to adjust a flow rate of exhaust gas in a first path, the first path connecting an upstream position of the turbine to a downstream position of the compressor; and a second recirculation system comprising a second adjuster to adjust a flow rate of exhaust gas in a second path, the second path connecting a downstream position of the turbine to an upstream position of the compressor, the controlling apparatus comprising: a calculator configured to calculate a target quantity being the sum of the flow rates of exhaust gas in the first path and second path in response to an operating state of a vehicle; a recirculation controller configured to execute a feedback control of at least one of the first adjuster and the second adjuster on the basis of the target quantity, and to switch between a single use and a combination use, the single use activating one of the first recirculation system and the second recirculation system, the combination use activating both the first recirculation system and the second recirculation system; and a pressure controller configured to execute a feedback control of an intake-system pressure in the downstream position of the compressor through adjustment of an opening of the vanes in response to the operating state, characterized in that a calculator configured to calculate a target quantity being the sum of the flow rates of exhaust gas in the first path and second path in response to an operating state of a vehicle; a recirculation controller configured to execute a feedback control of at least one of the first adjuster and the second adjuster on the basis of the target quantity, and to switch between a single use and a combination use, the single use activating one of the first recirculation system and the second recirculation system, the combination use activating both the first recirculation system and the second recirculation system; and a pressure controller configured to execute a feedback control of an intake-system pressure in the downstream position of the compressor through adjustment of an opening of the vanes in response to the operating state, characterized in that