Driver cabin of a working machine usable in agriculture or civil engineering

A driver's cab (13) of an agricultural or construction machinery work machine (1) is equipped with two A-pillars (16 and 17) provided in its front region as well as with at least two pillars (18, 19, 20, 21) running at a distance to these, wherein all pillars (16, 17, 18, 19, 20, 21) are arranged substantially vertically and support a cab roof (23). The driver's cab has a system for supplying fresh air and for its targeted distribution in its interior, wherein a blower (39) conveys the fresh air via at least one air conducting section running parallel to a cab floor (14) into air distribution channels, which extend along each of the A-pillars (16 and 17) and are provided with air outlet openings for flowing the fresh air into the interior of the driver's cab (13, 58). In order to provide a ventilation system and thus a cooling or heating system with which a pleasant air flow can be achieved for the driver under all climatic conditions, each of the air distribution channels is formed in a cladding element (37) which is assigned to the respective A-pillar (16 and 17), wherein the cladding element (37) has a wall course with a U-shaped cross-section with side walls and a front wall connecting these to one another, wherein to form an air distribution channel the side walls are connected to one another with spacing from their edges via a covering element designed as a flat profile and wherein the edges projecting over the covering element serve for fixing the cladding element (37) to the respective A-pillar (16 and 17).