The inventors succeeded in isolating a novel hemopoietin receptor gene (NR10) using a sequence predicted from the extracted motif conserved in the amino acid sequences of known hemopoietin receptors. It was expected that two forms of NR10 exists, a transmembrane type and soluble form. Expression of the former type was detected in tissues containing hematopoietic cells. Thus, NR10 is a novel hemopoietin receptor molecule implicated in the regulation of the immune system and hematopoiesis in vivo. These novel receptors are useful in screening for novel hematopoietic factors capable of functionally binding to the receptor, or developing medicines to treat diseases related with the immune system or hematopoietic system.