A walking training system comprising: a treadmill configured to prompt a trainee to walk; a display device installed such that the trainee views the display device while walking on the treadmill; a camera configured to image the trainee at an angle of view at which a gait of the trainee is recognizable; and a calculation unit configured to calculate a tilt of a body core of the walking trainee based on an image captured by the camera; wherein the walking training system further comprises: an evaluation unit configured to evaluate the gait; and a display control unit, wherein the display control unit is configured to: control the display device to display a body core line associated with the tilt, and an index indicating at least an end of a permissible range of a deflection of the body core line, cause the display device to display the body core line and the index such that the body core line and the index are superimposed on the image, render the body core line with a base point being defined near a heel of an affected leg of the trainee, render and display the range as a sector having a pivot at the base point, display an object based on an evaluation result from the evaluation unit, and display an indicator serving as the object included in the sector such that the indicator increases or decreases based on the evaluation unit. a treadmill configured to prompt a trainee to walk; a display device installed such that the trainee views the display device while walking on the treadmill; a camera configured to image the trainee at an angle of view at which a gait of the trainee is recognizable; and a calculation unit configured to calculate a tilt of a body core of the walking trainee based on an image captured by the camera; wherein the walking training system further comprises: an evaluation unit configured to evaluate the gait; and a display control unit, wherein the display control unit is configured to: control the display device to display a body core line associated with the tilt, and an index indicating at least an end of a permissible range of a deflection of the body core line, cause the display device to display the body core line and the index such that the body core line and the index are superimposed on the image, render the body core line with a base point being defined near a heel of an affected leg of the trainee, render and display the range as a sector having a pivot at the base point, display an object based on an evaluation result from the evaluation unit, and display an indicator serving as the object included in the sector such that the indicator increases or decreases based on the evaluation unit. an evaluation unit configured to evaluate the gait; and a display control unit, wherein the display control unit is configured to: control the display device to display a body core line associated with the tilt, and an index indicating at least an end of a permissible range of a deflection of the body core line, cause the display device to display the body core line and the index such that the body core line and the index are superimposed on the image, render the body core line with a base point being defined near a heel of an affected leg of the trainee, render and display the range as a sector having a pivot at the base point, display an object based on an evaluation result from the evaluation unit, and display an indicator serving as the object included in the sector such that the indicator increases or decreases based on the evaluation unit. control the display device to display a body core line associated with the tilt, and an index indicating at least an end of a permissible range of a deflection of the body core line, cause the display device to display the body core line and the index such that the body core line and the index are superimposed on the image, render the body core line with a base point being defined near a heel of an affected leg of the trainee, render and display the range as a sector having a pivot at the base point, display an object based on an evaluation result from the evaluation unit, and display an indicator serving as the object included in the sector such that the indicator increases or decreases based on the evaluation unit.