A seat adjustment apparatus of a vehicle that prevents a torque rod from falling off. A torque rod is rotatably supported by through holes, which are provided in a left base frame. The torque rod pivots with respect to base frames through pivoting of rear lifter links. A metal hook member is secured to the torque rod. The metal hook member includes a first engagement portion, second engagement portions, and a third engagement portion. The first engagement portion is passed through the torque rod and engaged with a torsion bar. The second engagement portions are engaged with the torque rod. The third engagement portion is provided at a position radially outward from the second engagement portions and engaged with the left base frame. The torsion bar is fixed to the torque rod through the metal hook member.