To provide a detergent low in cost and excellent in deposit removing capability.

The detergent is so composed that it contains 70.0-99.9 wt.% of a polyvalent carboxylic acid such as citric acid as the main component; 10.0-0.1 wt.% of an anionic surfactant such as a linear alkylbenzene sulfonate as the penetrant; and 20.0-0.1 wt.% of an aluminum salt such as aluminum hydroxide as the anticorrosive.