In a device for producing sponge iron from lumps of iron oxide in a reduction shaft (1), a hot, dust-containing and carbon monoxide-rich reduction gas is used. The reduction gas is generated in a gas generator by partial oxidation of solid carbon-containing materials and is in part supplied to the reduction shaft through several lateral reduction inlets (3) arranged at the same height around the circumference of the reduction shaft at the lower end of the reduction zone. The lumps of iron oxide are introduced into the reduction shaft through its top area and discharged as sponge iron at its bottom end. Additional reduction gas inlets (15) shaped as downwardly open channels (11) which extend from the outside to the inside of the reduction shaft and/or shaped as ducts which extend obliquely downwards from the outside to the inside of the reduction shaft and have open inner ends are arranged below the plane of the lateral reduction gas inlets. Reduction gas may thus be also supplied to the radial inner area of the reduction shaft, so that the introduction of dust by the reduction gas is not limited to the outer area of the bulk material in the reduction shaft.