A device for a wave-powered generator which is provided with at least one energy generator and lines for transferring energy to a consumer, the wave-powered generator comprising a main module provided with a running rod which is substantially vertical in its longitudinal extent, several supporting devices arranged around a portion of the running rod and arranged for sliding or rolling movement on surface portions extending in the longitudinal direction of the running rod, at least one sheave which is arranged to roll on the running rod, and transmission means which are arranged to translate the rotating motion of the at least one sheave into rotation of the drive shaft of the at least one generator; and a first float which is floatingly disposed in an area affected by waves and which is connected to the running rod by a primary driving line substantially of tensile strength.