An animal litter box system that can be used for a long time about 3 to 10 days and can prevent the occurrence of undesirable odors is to be provided, particularly to provide a liquid-absorbing sheet used for the animal litter box system. A liquid-absorbing sheet used for an animal litter box is characterized by comprising an antimicrobial and bacteriostatic part having both an antimicrobial property and a bacteriostatic property; or both of an antimicrobial part having an antimicrobial property and a bacteriostatic part having a bacteriostatic property.