Provided are a liquid detergent composition for hard surfaces which is excellent in detergency against oil spots including a degenerated oil such as a thermally degenerated oil; and a method for cleaning a hard surface using the liquid detergent composition. The liquid detergent composition for hard surfaces contains (a) an alkyl or alkenyl amine oxide in which the alkyl group or the alkenyl group has a predetermined number of carbons; a monooxyethylene or polyoxyethylene alkyl or alkenyl amine in which the alkyl group or the alkenyl group has 8 or more and 24 or less carbons and the number of added moles of the oxyethylene group is 1 or more and 8 or less; and water, wherein in the amine, the content of (b) a monooxyethylene or polyoxyethylene alkyl or alkenyl amine in which the alkyl group or the alkenyl group has a predetermined number of carbons and the number of added moles of the oxyethylene group is 1 or more and 3 or less is 50% by mass or more.