Quaternary change and phenomena in Southwest Japan are introduced from the viewpoint of (1) Quaternary environmental change, (2) Quaternary tectonics and active tectonics, (3) influence of human activities and on human societies, and (4) relationship to social activity including earthquake disaster mitigation and geopark activity. For each of the above four factors, some examples are introduced. Fundamental issues related to Quaternary change include the repetition of events and time interval of phenomena, the type and speed of phenomena as science targets, and the relationship to human activities and possibility of future estimation. It is significant to think about the time scale (temporal variation), the scale of the issues, and multiple different methodologies.