A heating device for a beverage-making machine has at least one water pump for supplying water to a first continuous-flow heater for generating hot water and to a second continuous-flow heater for generating steam. The first continuous-flow heater is switched over, if required, to steam generation and be connected up to the second continuous-flow heater. The second continuous-flow heater can also be switched over, if required, to hot-water generation and to be connected up to the first continuous-flow heater. A control means which is provided for controlling the switchover operations and the connections between the continuous-flow heaters, and is configured depending upon entries input into an operating unit and relating to the previous operating state of the heating device. In comparison with conventional appliances, the configuration envisaged for the heating device also makes it possible to provide relatively large quantities of hot water or steam in a relatively short period of time.