A warming-up system performing a catalytic converter warming-up method has an electric motor (1m) enabling a turbocharger (1) to increase the amount of air supplied to an internal combustion engine (2) regardless of the amount of exhaust gas flowing through a turbine (1t) of the turbocharger (1), a variable nozzle (1n) regulating the flow of exhaust gas through the turbine (1t), and an ECU (5) for controlling the operation of the electric motor (1m) and the variable nozzle (1n) and the amount of fuel supplied to the internal combustion engine (2). After the internal combustion engine (2) is started, the ECU (5) warms up the catalytic converter (4) by driving the electrical motor (1m) to forcibly rotate the turbine (1t), opening the variable nozzle (1n), and increasing fuel supply to the internal combustion engine (2).