Magnetic disk device and control method

According to one embodiment, a magnetic disk device includes a memory and a controller. The memory stores, for a predetermined track on a magnetic disk in the device, a counter, a counter threshold, and weights. The weights are individually set for divided areas of the predetermined track. The weights each have magnitude inversely proportional to a guaranteed number of times of data readout. When writing to an adjacent track of one or more of the divided areas is executed, the controller multiplies a number of times of writing by the weight corresponding to the one or more of the divided areas and adds the number of times of writing to the counter. When a numerical value of the counter reaches the counter threshold, the controller executes refresh to rewrite data in the predetermined track or executes reading for determining whether or not to perform the refresh.