Cleaning agent composition for medical-instrument cleaner

A detergent composition for a washer for medical devices, comprising a nonionic surfactant (A) represented by the formula (1) which is contained in the composition in an amount of not less than 1% by mass and not more than 40% by mass;

• at least one compound (B) selected from the group consisting of fatty acids having not less than 6 and not more than 10 carbon atoms and salts thereof which is contained in the composition in an amount of not less than 1% by mass and not more than 20% by mass in terms of a fatty acid;
• a cationic surfactant (C) represented by the formula (2);
• and water,
• the nonionic surfactant (A) being present in an amount of not less than 90% by mass on the basis of a total amount of whole nonionic surfactants contained in the detergent composition,
• a mass ratio of the at least one compound (B) selected from the group consisting of fatty acids having not less than 6 and not more than 10 carbon atoms and salts thereof to the cationic surfactant (C) [(B)/(C)] being not less than 20 and not more than 3000, and
• the detergent composition having a pH value of not less than 10 as measured at 25° C.,
• RO-[(EO)m/(PO)n]—H (1)
• wherein R represents an alkyl group having not less than 6 and not more than 18 carbon atoms;
• EO represents an ethanediyloxy group;
• PO represents a propanediyloxy group;
• m and n each represent an average molar number of addition of the ethanediyloxy or propanediyloxy group, and are each independently a number of not less than 1 and not more than 20;
• and the mark “/” represents that EO and PO may be added either in a random form or in a block form, and an order of addition of EO and PO is optional, and
• N+(R1)(R2)(R3)(R4).X− (2)
• wherein R1, R2, R3 and R4 are each independently an alkyl group having not less than 1 and not more than 24 carbon atoms or a benzyl group;
• and X− is a monovalent anion.