Magnetic disk device

Provided is a magnetic disk device capable of detecting incorrectness of parity bits generated from data in units of tracks. The magnetic disk device includes an HDC and an RWC. The HDC receives a plurality of data pieces from a host, generates and adds a first code to each data piece, and outputs the data piece to which the first code is added. The HDC calculates a logical exclusive OR with respect to the first code group, and outputs the obtained first information. The RWC performs data conversion and logical exclusive OR calculation on the plurality of data pieces to which the first code has been added, and outputs the plurality of data pieces after data conversion and the track parity obtained by the logical exclusive OR calculation. The RWC acquires a first code from a plurality of data slices. The RWC calculates a logical exclusive OR for a group of second codes, which is the acquired first code, and acquires second information. The RWC compares the first information with the second information and outp