To provide a fixture and a waterproof structure, capable of preventing breakage of a waterproof sheet and facilitating the work of providing the waterproof sheet on a structure.

A fixture 3 is for fixing a waterproof sheet 2 with a hook-and-loop fastener, which includes a waterproof sheet 4 and a hook-and-loop fastener 5 provided on a lower surface side of the waterproof sheet 4, to a skeleton 10 of a structure. The fixture 3 includes: a plate piece 6; a machine screw 8 which is provided on a lower surface side of the plate piece 6 and is a fixing part for fixing the plate piece 6 to the skeleton 10; and a hook-and-loop fastener 7 having a plurality of projections 71 projected upward from an upper surface of the plate piece 6 and engaged with a part of the hook-and-loop fastener 5 of a waterproof structure 1. The projection 71 has a pin-like projection body 711, and a head 712 provided on a distal end part of the projection body 711 and engaged with the hook-and-loop fastener 5.