To propose a new power generator using the movement of a linear magnetic body and to further improve a conventionally-proposed power generator. A configuration is provided including a tubular frame, a freely-moving magnetic body group that is arranged at the inner side of the tubular frame and that is obtained by integrating two or more magnetic bodies while homopolar bodies are opposed to each other, a coil provided on the tubular frame to have an interval to the outer periphery of the freely-moving magnetic body group and that is configured to alternately have a reversed winding direction, and an output line for outputting electric power from the coil. In a configuration in which the freely-moving magnetic body groups slide relative to each other in a coil axial direction to generate power, a transmission means is provided that is coupled to at least any one tip end of the freely-moving magnetic body group in a substantial axial direction, and power is generated in accordance with the movement of the transmission means.