A method for detecting a crater end of a continuously cast product, including installing an ultrasonic shear wave sensor for transmitting an ultrasonic shear wave to the continuously cast product and receiving the transmitted ultrasonic shear wave in a continuous casting machine, detecting based on variations of an ultrasonic signal received by the ultrasonic shear wave sensor that the crater end of the cast product is matched with the installed position of the ultrasonic shear wave sensor, calibrating a physical property value used in a calculation based on a heat condition equation such that the crater end computed based on the heat condition equation using casting conditions at that time is matched with the installed position of the ultrasonic shear wave sensor, and after the calibration, determining the crater end by the calculation based on the heat condition equation under respective casting conditions by using the calibrated physical property value.