The invention relates to a building machine, in particular a road-building machine, having running gear and a chassis which is fitted with a working unit which has one or more implements. The building machine has a stored-program control device for controlling the implements of the working unit and a device for displaying operational variables or operational states in the form of characters or images. In addition to the stored-program control device, the building machine has a centralized data processing device which is embodied in such a way that operational variables or operational states can be displayed as characters or images with the device for displaying operational variables or operational states. The exchange of data between the stored-program control device and the centralized data processing device is carried out via a first data bus, while the exchange of data between the data processing device and the device for displaying operational variables or operational states is carried out via a second data bus.