Pen-and-ink illustrations are attractive in that they have greater ability than photorealistic images to omit unimportant details, to clarify shapes and so on. Considering these advantages, we have created penand-ink-style animations. In our method, we treat 3D models as inputs and generate pen-and-ink-style line drawings in which the strokes of the illustration express the features of the original 3D geometry. In the illustrations generated, the density of strokes and the shapes of strokes represent the tone and the shape of the 3D models. If the models are moving/changing, we keep the coherence between the frames in order to generate smooth animations. For this purpose, the strokes are stored using a simple data structure that is able to retain the information in the previous frame.