To provide an electric actuator for improving reliability by enhancing position detecting accuracy without using a multistage gear even if using a potentiometer by directly detecting a position.

A ball screw mechanism 8 is constituted of a screw shaft 15 connected to an electric motor 3, integrally supported to a drive shaft 7 so as to be non-rotatable with respect to a housing 2 and movable in the axial direction, and a nut 16 out-fitted to the screw shaft 15 via a large number of balls 17 and supported so as to be rotatable and immovable in the axial direction via a rolling bearing 18. The potentiometer 9 is positioned on and fixed to a reverse surface of the housing 2 in an upper part of the drive shaft 7. A tip of a joint part 11 is arranged so as to project to the inside of the housing 2, and one end of a rocking link 12 is connected to the tip. The other end of the rocking link is engaged with a pin 13 projected on the driving shaft 7, and arranged so that a pendulum motion can be performed by being interlocked with the linear motion of the drive shaft 7.