Flexible substrate and electronic device

A flexible substrate inserted in a hinge electrically connects circuit substrates, which are housed in a first casing and a second casing, respectively, to each other. The substrate has a power supply line and signal lines which are formed from a wiring conductor. Slits are opened in border portions of the power supply line in a cranked portion. The slits opened in the border portions of the power supply line make the rigidity of the border portions lower than in prior art. This means that a base is prevented from squashing the wiring conductor (power supply line) when the substrate is bent and that stress concentration on the border portions can accordingly be avoided. As a result, cracks in the border portions are prevented and the power supply line (wiring conductor) is protected against wire breakage.