To provide a noise absorption device absorbing both normal mode noise and common mode noise by a single noise absorption device, and also to provide a noise absorption structure with countermeasures against noise by using the noise absorption device.

The noise absorption device 1 includes a pair of split cores 2 and 2 having U-shape in cross section which can be coupled as a cylindrical magnetic core containing a cavity. On its inner wall surface 2A, Projections 3 are protruded at three points corresponding to the middle part of major side of rectangular cross section of the cavity. Two electric wires are so inserted as to sandwich the projection 3, the electric wires are twisted among the three projections 3, and then the pair of split cores 2 is coupled together. Here, two electric wires are individually enclosed by a magnetic body from an outer periphery in a section adjacent to the projection 3, and in a section unadjacent to the projection 3, the two electric wires are collectively enclosed by the magnetic body.