The disclosure relates to a linear actuator including a base, a linear motor, a load cell and a rotary motor. The linear motor is disposed on the base and includes a fixed coil module and a movable magnetic backplane. The fixed coil module is fixed on the base, and the movable magnetic backplane is configured to slide relative to the fixed coil module along a first direction. The rotary motor is rotated around a central axis in parallel with the first direction. The load cell has two opposite sides parallel to the first direction, respectively. The movable magnetic backplane of the linear motor and the rotary motor are connected to the two opposite sides of the load cell, respectively. The load cell is subjected to a force applied thereto by the rotary motor and parallel to the first direction, and configured to convert the force into an electrical signal.