According to one embodiment, a disk device includes magnetic disks, a first head gimbal assembly, a first damper, and a carriage. The first head gimbal assembly includes a first magnetic head, a first load beam, and a first base plate. The first load beam supports the first magnetic head. The first base plate is connected to the first load beam. The first damper includes a first viscoelastic material, and a first member attached to the first viscoelastic material. The carriage rotates about a rotation axis to move the first magnetic head along a recording surface of a first magnetic disk. The carriage includes an arm, and a first flat surface of the arm. The first flat surface faces the recording surface of the first magnetic disk. The first base plate and the first viscoelastic material are fixed to the first flat surface.