In a fault monitoring method for a portable radio communication terminal, plural portable radio communication terminals communicate with an inventory controller via a radio communication base station. In the portable radio communication terminal in a commodity management system, when the number of retrying times of radio communication between the portable radio communication terminal and the radio communication base station exceeds a predetermined number of times, the portable radio communication terminal automatically executes a test of a radio communication section and displays a fault on a display section of the portable radio communication terminal when a fault occurs.