a processor,

wherein the processor compares a servo band signal, which is a result of reading a servo band in which a servo pattern is recorded from a magnetic tape including the servo band by a servo reading element, with a threshold value to detect a servo pattern signal indicating the servo pattern, and

the threshold value is determined in accordance with an angle formed by the servo pattern and the servo reading element,

wherein the servo pattern is at least one linear magnetization region pair,

the linear magnetization region pair includes a first linear magnetization region which is linearly magnetized, and a second linear magnetization region which is linearly magnetized,

the first linear magnetization region and the second linear magnetization region are inclined in opposite directions with respect to a first imaginary straight line along a width direction of the magnetic tape,

the angle is classified into a first angle formed by the first linear magnetization region and the servo reading element, and a second angle formed by the second linear magnetization region and the servo reading element,

the threshold value is classified into a first threshold value and a second threshold value,

the first threshold value is determined in accordance with the first angle, and

the second threshold value is determined in accordance with the second angle.