A control device for a supercharging system for supplying compressed intake air to an engine, the supercharging system comprising a supercharger configured to compress intake air to be supplied to the engine, a boost-pressure control unit configured to control a boost pressure of the supercharger, and a control device configured to control the boost-pressure control unit, and the control device comprising: an engine controller comprising an engine signal input part to which various sensor signals related to an operational state of the engine are to be inputted, and an engine control part configured to control an operational state of the engine and to compute a target boost pressure of the supercharger on the basis of the sensor signals inputted into the engine signal input part; and a turbo controller comprising a turbo signal input part to which at least sensor signals related to an operational state of the supercharger are to be inputted from among the various sensor signals related to an operational state of the engine, and a turbo control part configured to compute a margin of the supercharger on the basis of the sensor signals inputted to the turbo signal input part, the turbo controller comprising a control part and a signal input part provided separately and independently from the engine controller, wherein the control device is configured to compute a target boost-pressure corrected value by correcting the target boost pressure in accordance with a magnitude of the margin computed by the turbo control part, and to control the boost-pressure control unit so that the boost pressure of the supercharger reaches the target boost-pressure corrected value and wherein the margin is a surge-pressure margin which is a ratio of a difference between a surge pressure and a boost pressure to the surge pressure, where the surge pressure is a limit pressure at which surging occurs. an engine controller comprising an engine signal input part to which various sensor signals related to an operational state of the engine are to be inputted, and an engine control part configured to control an operational state of the engine and to compute a target boost pressure of the supercharger on the basis of the sensor signals inputted into the engine signal input part; and a turbo controller comprising a turbo signal input part to which at least sensor signals related to an operational state of the supercharger are to be inputted from among the various sensor signals related to an operational state of the engine, and a turbo control part configured to compute a margin of the supercharger on the basis of the sensor signals inputted to the turbo signal input part, the turbo controller comprising a control part and a signal input part provided separately and independently from the engine controller, wherein the control device is configured to compute a target boost-pressure corrected value by correcting the target boost pressure in accordance with a magnitude of the margin computed by the turbo control part, and to control the boost-pressure control unit so that the boost pressure of the supercharger reaches the target boost-pressure corrected value and wherein the margin is a surge-pressure margin which is a ratio of a difference between a surge pressure and a boost pressure to the surge pressure, where the surge pressure is a limit pressure at which surging occurs.