Formed with an eperisone salt and an acidifying agent, but the acidity of a 0.5% (W / V) aqueous solution is pH 0.5 to pH 5.6, and the acidifying agent is added to an acid pH adjusting agent or water. A stabilized eperisone pharmaceutical composition characterized in that it is selected from excipients exhibiting a pH of 5.0 or less when suspended, dissolved, swollen or mixed. [Selection] Figure 1エペリゾン塩と酸性化剤を含んで形成されるが、0.5%(W/V)水性溶液の酸度がpH0.5~pH5.6であり、前記酸性化剤は酸性pH調節剤又は水に懸濁、溶解、膨潤又は混和された際にpH5.0以下を示す賦形剤のうちから選択されることを特徴とする安定化されたエペリゾン医薬造成物。【選択図】図1