The invention relates to a method of manufacturing porous construction items, such as bricks, ceramic tiles, roof tiles, large-sized wall blocks, pavement items etc. The technical result of the invention is a reduction in energy consumption while preserving the physicochemical properties. The method of manufacturing porous construction items from natural clay raw material that is capable of swelling comprises the preparation of the raw material, moulding, two-stage heating with retention until swelling occurs, and stabilization. Moreover, the first heating stage takes place before the moulding and is carried out simultaneously with the transport of the raw material to the mould filling zone. The moulding takes place in a mould designed as a muffle furnace with a lid, and the second heating stage occurs at a temperature of no less than 1250°C for no less than 10 minutes. Stabilisation occurs in a tilted tunnel furnace, wherein the inside temperature at the entry is no less than 900°C with further cooling of the finished product at a rate of no more than 120 degrees/hour so that the items at the exit are cooled to no more than 30-40°C.