The present invention relates to a composition of an intracanal medication agent for medicating root canals for a predetermined period of time. According to one aspect of the invention, there is provided an intracanal medication composition based on a calcium hydroxide component, comprising: calcium hydroxide or a calcium hydroxide producing component as a powder component; and at least one of diethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP) and diethylene glycol monoethyl ether (DEGEE) as a liquid component.