A device is provided which is capable of determining an amount of exercise involved in walking, as well as of obtaining quantitative information about visceral fat in the abdominal part of a subject and which can be used handily by being carried with the subject. The visceral fat determining device with a step-counting function is configured as follows. The visceral fat determining device has a step-counting means for counting the number of steps involved in exercise such as walking done by a subject and a main body shaped to be portable. When body data of the subject such as the waist size of the subject is inputted to the visceral fat determining device through a manipulation section, the visceral fat determining device is capable of performing a computation of the body data based on a predetermined computing formula for obtaining quantitative information about the abdominal visceral fat of the subject.