Magnetic disk device

A magnetic disk device comprising:

• a magnetic disk;
• a magnetic head configured to carry out read/write from/to the magnetic disk;
• a control device configured to control the magnetic head;
• and
• a regulator configured to supply voltage to the control device, wherein
• the control device comprises a power source control section configured to change an output voltage value of a voltage supplied to the control device from the regulator on the basis of a voltage control parameter and a control section configured to, when the magnetic head makes access to a zone set on the magnetic disk, set a voltage control parameter provided in such a manner as to be correspondent to the zone to the power source control section,
• the control section carries out feedback control of the regulator such that a value of the voltage supplied from the regulator becomes a target voltage value and starts the feedback control a predetermined time earlier when a position from/to which the magnetic head reads/writes data is switched from an inner circumferential side to an outer circumferential side and if a first time until switching of the voltage of the regulator by the feedback control is completed is larger than a second time until moving of the magnetic head is completed.