A walking training system comprising: a treadmill; a center-of-gravity position detection unit (225, 222) configured to detect a center-of-gravity position of a trainee from a load received from a sole of the trainee on a belt of the treadmill; a posture detection unit (226, 217) configured to detect a posture of the trainee; a center-of-gravity position estimation unit configured to estimate the center-of-gravity position of the trainee from the detected posture of the trainee; a determination unit configured to determine whether a difference between the detected center-of-gravity position and the estimated center-of-gravity position (CPx) exceeds a predetermined value; and a notification unit configured to, when the determination unit determines that the difference exceeds the predetermined value, send a notification notifying that the difference exceeds the predetermined value, wherein the center-of-gravity position detection unit is a load distribution sensor that is installed under the belt of the treadmill such that the load distribution sensor is not interlocked with the belt and is configured to detect a distribution of the load received from the sole of the trainee on the belt of the treadmill, and wherein: the center-of-gravity position detection unit (225, 222) includes: a pair of load sensors configured to be attached to respective soles of a right leg and a left leg of the trainee; and a first image capturing unit configured to capture images of at least the right and left legs of the trainee; and the center-of-gravity position detection unit (225, 222) is configured to detect the center-of-gravity position of the trainee based on loads detected by the load sensors and respective positions of the right and left legs of the trainee identified from the images captured by the first image capturing unit. a treadmill; a center-of-gravity position detection unit (225, 222) configured to detect a center-of-gravity position of a trainee from a load received from a sole of the trainee on a belt of the treadmill; a posture detection unit (226, 217) configured to detect a posture of the trainee; a center-of-gravity position estimation unit configured to estimate the center-of-gravity position of the trainee from the detected posture of the trainee; a determination unit configured to determine whether a difference between the detected center-of-gravity position and the estimated center-of-gravity position (CPx) exceeds a predetermined value; and a notification unit configured to, when the determination unit determines that the difference exceeds the predetermined value, send a notification notifying that the difference exceeds the predetermined value, the center-of-gravity position detection unit (225, 222) includes: a pair of load sensors configured to be attached to respective soles of a right leg and a left leg of the trainee; and a first image capturing unit configured to capture images of at least the right and left legs of the trainee; and a pair of load sensors configured to be attached to respective soles of a right leg and a left leg of the trainee; and a first image capturing unit configured to capture images of at least the right and left legs of the trainee; and the center-of-gravity position detection unit (225, 222) is configured to detect the center-of-gravity position of the trainee based on loads detected by the load sensors and respective positions of the right and left legs of the trainee identified from the images captured by the first image capturing unit.