PURPOSE:To obtain the title promoter capable of selectively rearing and promoting eucaryotic cell and eucaryotic microorganism by adding a hydrophilic solvent extract of propolis as an active ingredient. CONSTITUTION:Propolis, preferably grown in Brazil is as necessary preliminarily extracted with an organic solvent such as chloroform and then a hydrophilic solvent such as water or ethanol is added thereto and the propolis is subjected to extraction treatment at 20-30 deg.C for 24-48hr and filtered to provide the aimed promoter. Furthermore, eucaryotic microorganism of filamentous fungus such as the genus Saccharomyces and eucaryotic cell of animal cell of silkworm, etc. and plant cell of saffron, etc., are inoculated into a culture medium to which the promoter is added, preferably at an amount of 25-30g per l culture medium for cell culture to carry out culture.