To provide a linear actuator that achieves improvement in mountability and versatility even if it is a sensorless linear actuator.

The linear actuator 1 is provided with: a rod 2 in which a field 3 comprising a cylindrical permanent magnet 4 is mounted on its outer periphery; and a coil holding member 5 that allows the rod 2 to be inserted thereinto and holds a coil 6 facing the outer periphery of the field 3. The linear actuator generates a thrust force for axially displacing the rod 2 and the coil holding member 5 relative to each other. The rod 2 includes a hollow inner rod 7 inserted into the rod 2 and connected to the coil holding member 5. Either a cylindrical commutator 8 or brushes 19, 20, and 21 connected to a power supply is/are provided inside the rod 2. The other the cylindrical commutator 8, or the brushes 19, 20, and 21 connected to the coil 6 is/are provided on the outer periphery of the inner rod 7.

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