We have compared magnetotail variations with auroral activities during 8 substorms using GEOTAIL and Polar UVI data. In the 1737 UT substorm event on 15 December 1996, auroral breakups and intensifications were highly correlated with fast plasma flows with the variations in the north-south magnetic field and the total pressure in the magnetotail. GEOTAIL was located around X ~ -21 RE, and several fast tailward flows were observed in the early expansion phase with the southward magnetic field and the total pressure enhancement, associated with plasmoids. These flows were observed simultaneously with or within about 1 min of auroral breakups or pseudobreakups. In the late expansion or recovery phase, some fast Earthward flows were observed with the northward magnetic field as well as the total pressure enhancement slightly earlier than small auroral intensifications. These observations imply that the activation and tailward retreat of the near-Earth neutral line is intermittent. Furthermore, including the other events, we found that the total pressure decrease in the magnetotail can be correlated with auroral activity better than the fast plasma flow. The total pressure in the magnetotail significantly decreases during auroral breakups or poleward expansions of the auroral bulge but slightly decreases during pseudobreakups. The duration of the expansion and the maximum size of the auroral bulge are closely correlated with the duration and amount of total pressure decrease in the magnetotail, respectively. These results imply that the magnitude of auroral activities associated with substorms depends on that of energy dissipation in the magnetotail.