A hinge device includes: a first and a second hinge components having a common reference axis; and a power generating device. The first and the second hinge components are engaged with each other, so as to be rotatable about the reference axis relative to each other, and so that one of the first and the second hinge components supports the other. The power generating device includes a housing and an input shaft, and generates electric power by rotation of the input shaft. The housing of the power generating device is fixed to the first hinge component, so that the input shaft of the power generating device is positioned on the reference axis. The input shaft of the power generating device is restrained to the second hinge component with respect to the direction of rotation about the reference axis, so that the input shaft of the power generating device rotates by as much as rotation of the second hinge component when the second hinge component rotates about the reference axis.