Abstract: A heat treatment apparatus for thin spheroidal graphite cast iron products comprising a cast iron product remover for removing a thin spheroidal graphite cast iron product from a casting mold; a continuous furnace having an inlet positioned near the cast iron product remover, the continuous furnace comprising a uniform temperature zone kept at a temperature equal to or higher than an A.sub.3 transformation point of the thin spheroidal graphite cast iron product and a cooling zone downstream of the uniform temperature zone; a first conveying means for the thin cast iron product disposed between the cast iron product remover and the inlet of the continuous furnace; and a second conveying means for the thin cast iron product moving through the continuous furnace, the thin cast iron product being conveyed to the second conveying means by means of the first conveying means immediately after removed from the casting mold and introduced into the continuous furnace by means of the second conveying means.