The invention relates to a continuous steam generator with circulating atmospheric fluidised-bed combustion, comprising a turbulence combustion chamber (3). Said turbulence combustion chamber (3) is defined by encircling walls (4) essentially on all sides, consists of gas-permeable tubular walls provided with essentially vertical tubes (5), and comprises at least one funnel (6, 7) in its lower region. The turbulence combustion chamber (3) has at least one essentially vertically arranged heating surface (8) provided with vertical tubes (9), said heating surface (8) consisting of a welded tube-web-tube combination, and a water/steam working medium flows through the tubes (5, 9) of the encircling walls (4) and the heating surface (8). All of the tubes (5, 9) of the encircling walls (4) and the heating surface (8) are embodied as evaporator heating surfaces and are mounted in parallel for the circulation of the entire working medium to be evaporated. In addition, all of the tubes (5) of the encircling walls (4) have an inner smooth surface, and the heating surface (8) extends between the bottom of the combustion chamber (4.1) or the upper edge (24) of the funnel, and the top of the combustion chamber (4.3). (FIG.3 &5)