A chip-on-film device including a flexible circuit film having a wire, a passivation layer having a hole, an adhesive layer, a pad, an interconnection, and a bump is provided. A part of the adhesive layer is disposed in the hole. The pad is disposed under the passivation layer, and a part of the pad is disposed under the hole. A part of the interconnection is disposed under the passivation layer, and disposed at a side of the pad, wherein the interconnection does not touch the pad. A part of the bump is disposed on the adhesive layer. The bump is electrically connected to the pad via the adhesive layer. The bump is welded on the wire. A part of a first part of the bump overlaps the pad, and a second part of the bump extends to an outside of the pad and at least partially overlaps the interconnection.