A visualization system includes: a first creation section configured to create, for each product manufacturing unit, a line segment connecting a start or end time of a first step to a start or end time of a subsequent second step; a second creation section configured to identify, based on a change log of a step characteristic factor at each manufacturing step, any change in step characteristic factor observed at the first and second steps, and to create a display object representing magnitude of the change in step characteristic factor or including a region representing an attribute of the changed step characteristic factor; and a display control section configured to cause: to display a line segment representing the time axis, created by the first creation section, and the display object, and to display the display objects over positions of the start or end times on time axes of their associated steps.