To provide an electric actuator capable of keeping an actuator movable portion action on a side which can always secure safety by detecting malfunction of the actuator movable portion.

This electric actuator includes a case 1, an electric motor 2, and a ball screw mechanism 3 having a ball nut 5 screwed with a ball screw 4. Besides, an output shaft 7 of which one end facing the inside of the case 1 is jointed with the ball nut 5 is provided. A displacement detector 11 for detecting the malfunction of the actuator movable portion is provided. The displacement detector 11 is provided with a displacement sensor 12 and a computer 13, and the displacement sensor 12 is constituted out of a pair of Hall elements 14a, 14b attached so as to face a guide groove 10 of the case 1, and a permanent magnet 15 attached at a lock member 9.