The present invention has as an object to provide a bone metabolism improving agent that improves bone metabolism in a chronic renal failure patient receiving blood purification therapy such as hemodialysis, hemofiltration and hemodiafiltration. An acetic acid- and/or acetate salt-free bone metabolism improving agent that contains citric acid and/or a citrate salt as electrolytes and further contains another/other electrolyte/electrolytes and glucose solely or in combination is provided. A bone metabolism improving agent formulated into a dialysate or a substitution fluid having effects of improving bone metabolism including bone metabolism improvement in adynamic bone disease and especially in bone agenesis is also provided.