In a torque converter provided with a lockup device, performance of a torsion spring is improved, preferably by increasing its size, while suppressing an increase of an axial dimension of the torque converter. One panel is connected to the other for movement about an axis to permit movement of the one between a closed position, wherein the panels are stacked, and an open position, wherein the panels extend away from one another. The side support sections extend so that portions thereof engage against the inner surface of the solar absorbing tube.