A valve timing controller includes: an outer rotor; an inner rotor relatively rotating inside of the outer rotor; a torsion coil spring having a fixed end connected with the inner rotor, and a free end connected with the outer rotor; and a bush rotor coaxially projected from the outer rotor or the inner rotor to support the torsion coil spring in a radial direction. The torsion coil spring biases the inner rotor while being connected with the outer rotor by being torsionally deformed according to a relative rotation of the inner rotor to the outer rotor. A load acting from a first turn of the torsion coil spring adjacent to the free end is smaller than a load acting from a wound part of the torsion coil spring between the first turn and the fixed end.