Disclosed is a file memory unit having a casing for accommodating a head positioning mechanism and a magnetic recording disk virtually in sealed manner, and a frame for supporting the casing resiliently. The unit has the provision of a shock absorbing facility for absorbing the vibration created by the head positioning mechanism and the vibration and impact applied from the outside. The shock absorbing facility has a unitary structure having a first spring constant for absorbing relatively small vibration created by the casing, a second spring constant for absorbing the vibration applied from the outside, and a third spring constant for absorbing the impact applied from the outside.