A method for supplying upper combustion air from an upper air supply level (10, 11) into a fluidized-bed boiler (1), which boiler is provided with at least a lower air supply (9) underneath the fluidized bed (4) and a fuel supply means (5) above the fluidized bed, as well as one or more upper air supply levels (10, 11) for supplying upper air into the furnace (2) of the boiler, which furnace is limited by a front wall (12), side walls (14, 15) and a rear wall (13) with the nose (6) of the boiler, the air supply level (10, 11) underneath the nose comprising at least side air jets (17) placed in the side walls (14, 15) of the furnace (2) On the air supply level (10, 11), which also comprises at least one or more primary air jets (16) placed in the front wall (12) of the furnace (2), an air flow (18) is supplied from the primary air jet into the furnace, which air flow (18) is stronger than the air flow (19) supplied from the side jet (17) into the furnace. The invention also relates to an air arrangement and a fluidized-bed boiler (1) implementing the method.