To provide a linear generator capable of achieving simplification in the structure of a generator and reduction in size and weight thereof, and stably obtaining efficient power generation.

The linear generator has a fluid pressure cylinder structure in which a fluid pressure in a left fluid pressure chamber 4 contacting a left end wall 2 of a cylinder 1 and a fluid pressure in a right fluid pressure chamber 5 contacting a right end wall are alternately applied to a piston 6 in the cylinder 1, thereby allowing the piston 6 to reciprocated in an axial line direction. The linear generator is configured in such a way that a permanent magnet band 9 is formed between a left fluid pressure receiving surface 7 contacting the left fluid pressure chamber 4 of the piston 6 and a right pressure receiving surface 8 contacting the right fluid pressure chamber 5, an electromotive coil band 11 over the right and left fluid pressure chambers 4, 5 is formed on a cylindrical wall between the right and left end walls 2, 3 of the cylinder 1, and the power generation in the electromotive coil band 11 is induced by reciprocation in an axial line direction of the piston 6 having the permanent magnet band 9.