There is provided an electric actuator including a motor part, a deceleration mechanism, an output part, and a housing. The housing has a housing main body and a lid member. An output shaft is positioned at a first corner of the housing. The lid member and the housing main body are fastened by bolts. The bolts include corner bolts positioned at respective corners of the housing other than the first corner and an intermediate position bolt positioned at the intermediate between the first corner and a second corner adjacent to the first corner. In a plane view, the intermediate position bolt is positioned on the side of the planar center with respect to an edge connecting the first corner and the second corner and on the side of an outer edge with respect to an imaginary line connecting the center of the output shaft and the second corner.