To provide a small-size linear drive actuator which is rotary drivable.

A linear drive actuator which is rotary drivable is composed of a linear drive unit 1 and a rotary drive unit 2. The linear driving unit 1 is constituted of a stator 3 having a yoke 5 and coils 6a and 6b and a mover 4 having a drive shaft 7 and permanent magnets 8a and 8b. The rotary drive unit 2 has a stator 15, having a yoke 17 and a coil 18 and a mover 16, having a ball spline 20 and a permanent magnet 19 which rotary together with the drive shaft 7. The drive shaft 7 rotates together with the mover 16 by means of the ball spline 20, while being freely movable in the axial direction. When the coils 6a and 6b are excited, the drive shaft 7 is driven in the axial direction, and when the coil 18 is excited, the drive shaft 7 is driven to rotate.