Abstract: A physiological information processing apparatus including: a processor; and a memory that stores a computer-readable command. When the computer-readable command is executed by the processor, the physiological information processing apparatus acquires physiological information data indicating physiological information of a subject, acquires a value of a parameter relevant to an autonomic nerve function of the subject in each of first time intervals based on the physiological information data, acquires an abnormality index value indicating an extent of abnormality in the autonomic nerve function of the subject based on the values of the parameter acquired in the first time intervals respectively, and displays information relevant to the abnormality index value.