<p>A process for producing a polyrotaxane in a high yield and at a satisfactory cost without using a large excess of a pseudopolyrotaxane and/or without using a large excess of an activated reagent. The process for polyrotaxane production comprises: a clathration step in which a carboxylated polyethylene glycol which is a polyethylene glycol carboxylated at each end is mixed with cyclodextrin molecules to obtain a pseudopolyrotaxane which comprises cyclodextrin molecules which include the carboxylated polyethylene glycol in their spaces as if the cyclodextrin molecules are spitted with the carboxylated polyethylene glycol; and a blocking step in which the pseudopolyrotaxane is reacted with blocking groups having -NH2 or -OH to obtain a polyrotaxane terminated at each end by a -CO-NH-(blocking group) or -CO-O-(blocking group).</p>
