A biosensor device includes a substrate, an oxide layer and a sensing wire. The oxide layer is disposed on the substrate. The sensing wire is disposed on the oxide layer. The sensing wire is provided to receive target biomolecules. The sensing wire includes at least one first section extending along a first direction and at least one second section extending along a second direction. The at least one first section is continuous with the at least one second section. The first direction is different from the second direction. The sensing wire has a width and a total length and a ratio of the total length to the width is larger than 500.