This invention has an object to provide a means for providing a calcium phosphate sintered body particle group that does not cause a phenomenon of bubble generation in any use mode thereof, and further has a smaller particle diameter.There is provided a ceramic particle group containing spherical ceramic particles, which is characterized in that the ceramic particle has a particle diameter within a range of 10 nm to 700 nm, and is a calcium phosphate sintered body particle, and further the ceramic particle group contains no calcium carbonate.