Disclosed are a powder of indium-tin oxide aciculae suitable as an electroconductive filler for an electroconductive ink to be used for forming a transparent electroconductive film, a method for producing a raw material to be used for producing the powder of indium-tin oxide aciculae, which has a major diameter of 5 .mu.m or more and a ratio of the major diameter to the minor diameter of 5 or more, an electroconductive paste capable of forming a light-transmitting electroconductive film having sufficient electroconductivity and light transmittance by printing, such as screen-printing, followed by high-temperature baking, and a light-transmitting electroconductive film to be formed from the paste. The raw material is produced by heating and concentrating an aqueous solution containing indium ions and nitrato ions to form a high-viscosity slurry followed by separating a powder of aciculae from the slurry. By calcining the raw material, a powder of indium-tin oxide aciculae is produced.