A sheet treating apparatus has a container containing a plurality of sheets therein, a recorder for effecting recording on the sheets, a substantially straight path for conveying the recorded sheets and a heat-developer for heat-developing the sheets in the path. The container and/or the recorder are disposed under the heat-developer, are vertically overlapped with one another, and may be vertically overlapped with the heat-developer. The container and the straight path are disposed so that the straight path and the sheets in the container may be substantially parallel or substantially orthogonal to one another.