The experimental activities of the Plasma Physics Laboratory at Kyoto University are reported. The laboratory has been conducting the Heliotron project which is a research project on plasma confinement and heating comprising the heliotron machines Heliotron A, B, C, D, DM, DR and E. The heliotron field is one of the basic plasma-confining field configurations investigated since 1959 in the laboratory. In the paper, the results of experimental studies on the Heliotron D, DM and E machines are reported.