A hinge device 100 includes: a one-piece hinge base 20 such that connecting hinge bases 21a, 21b in which rotational shaft portions 23a, 23b are protrusively provided in the same direction by a burring process are connected together through a hinge base connecting part 22; and a one-piece holder 10 such that connecting holders 11a, 11b having click washers 30a, 30b attached thereto are connected together through a holder connecting part 12, wherein the one-piece holder 10 is assembled to the one-piece hinge base 20 from one direction.