A magnetic tape device includes a TMR head as a servo head; and a magnetic tape which includes a magnetic layer including ferromagnetic hexagonal ferrite powder and a binding agent, and including a servo pattern. The XRD intensity ratio (Int(110)/Int(114)) of the hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer using an In-Plane method is 0.5 to 4.0. The vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00. The center line average surface roughness Ra measured regarding the surface of the magnetic layer is less than or equal to 2.0 nm, and the logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is less than or equal to 0.050.