A polyglycerol composition contains diglycerol, triglycerol, and tetraglycerol each in a content of 5 percent by weight or more, has a total content of diglycerol, triglycerol, and tetraglycerol of 75 percent by weight or more, has a total content of higher polyglycerol components of 10 percent by weight or less, the higher polyglycerol components each having a degree of polymerization of 7 or higher, and is substantially free from chlorine atom. A process prepares a polyglycerol composition by reacting glycerol and/or a polyglycerol with glycidol in the presence of an activated carbon catalyst.