A physiological parameter measuring apparatus is configured to perform a screening for a likelihood of the critical congenital heart disease, based on the oxygen saturations at two locations on a body of a patient and the difference between the oxygen saturations, and to display the likelihood as a result of the screening. The physiological parameter measuring apparatus manages, with respect to each patient, a scheduled time for starting the screening, the result of the screening, and information relating to the patient. The physiological parameter measuring apparatus can display a first screen containing information relating to the scheduled time, a second screen for receiving the instruction to perform the screening, and a third screen containing the result of the screening. A physiological parameter measuring system includes sensors to be attached to the body at the two locations, and the physiological parameter measuring apparatus.