Provided is a bone regenerative agent which can repair a bone defect site with preventing from remaining at the bone defect site. The bone regenerative agent comprises zinc subcarbonate containing hydrozincite. It is preferred that the zinc subcarbonate has a Zn2+ ion elution amount of 0.1 ppm by mass or more after an elution test and also has a pH value of 7.2 or more and less than 8.3 after an elution test. It is preferred that some carbonate ions in the hydrozincite are substituted by sulfate ions or chloride ions. It is preferred that the bone regenerative agent is applied to a bone defect site.