It is an object of the present invention to provide an animal urinary function measuring device and an animal urinary function measuring method each with high accuracy in sampling a urine amount of an animal. There are provided an accommodating portion which accommodates an animal other than humans, a collecting portion which is provided below the accommodating portion and collects urine discharged by the animal in the accommodating portion, a reticulated portion which is provided below the accommodating portion, allows the passage of the urine of the animal into the collecting portion, collects an object other than the urine, and whose wire diameter of a net thereof being not more than 0.5 mm and whose mesh size being not less than 1 mm2 and not more than the maximum mesh size determined by at least one of the excrement of the animal accommodated in the accommodating portion and a predetermined object used to accommodate the animal in the accommodating portion, a measuring portion which measures the weight of the urine collected by the collecting portion, and a data recording portion which records data measured by the measuring portion.