An electric linear actuator comprising: a housing; an electric motor mounted on the housing; and a speed reduction mechanism for transmitting the rotational power of the electric motor to a ball screw mechanism via a motor shaft with reducing the motor speed; the ball screw mechanism being adapted to convert the rotational motion of the electric motor transmitted via the speed reduction mechanism to an axial linear motion of a driving shaft and comprising a nut formed with a helical screw groove on its inner circumference and rotationally but axially immovably supported by bearings (20, 20) on the housing, and a screw shaft coaxially integrated with the driving shaft, formed with helical screw groove on its outer circumference corresponding to helical screw groove of the nut, adapted to be inserted into the nut via a large number of balls, and supported on the housing not rotationally but axially movably, wherein the housing comprises a first housing and a second housing arranged with their end faces being abutted against each other, characterized in: that joining surfaces (35, 36) of the end faces of the first and second housings (2a, 2b) are sealed by curing liquid curable material, that the joining surfaces of the first and second housings (2a, 2b) are formed with a first void and a second void arranged oppositely to and communicating with the first void, wherein the curable material is injected to the first void, and wherein a volume of the curable material is larger than that of the first void and smaller than total of volumes of the first and second voids (37, 38) and that the joining surfaces (35, 36) of the first housing and the second housing have a portion where the housings (2a, 2b) are in direct contact with each other and a portion where the curable material is interposed. a housing; an electric motor mounted on the housing; and a speed reduction mechanism for transmitting the rotational power of the electric motor to a ball screw mechanism via a motor shaft with reducing the motor speed; the ball screw mechanism being adapted to convert the rotational motion of the electric motor transmitted via the speed reduction mechanism to an axial linear motion of a driving shaft and comprising a nut formed with a helical screw groove on its inner circumference and rotationally but axially immovably supported by bearings (20, 20) on the housing, and a screw shaft coaxially integrated with the driving shaft, formed with helical screw groove on its outer circumference corresponding to helical screw groove of the nut, adapted to be inserted into the nut via a large number of balls, and supported on the housing not rotationally but axially movably, wherein the housing comprises a first housing and a second housing arranged with their end faces being abutted against each other, characterized in: that joining surfaces (35, 36) of the end faces of the first and second housings (2a, 2b) are sealed by curing liquid curable material, that the joining surfaces of the first and second housings (2a, 2b) are formed with a first void and a second void arranged oppositely to and communicating with the first void, wherein the curable material is injected to the first void, and wherein a volume of the curable material is larger than that of the first void and smaller than total of volumes of the first and second voids (37, 38) and that the joining surfaces (35, 36) of the first housing and the second housing have a portion where the housings (2a, 2b) are in direct contact with each other and a portion where the curable material is interposed. that joining surfaces (35, 36) of the end faces of the first and second housings (2a, 2b) are sealed by curing liquid curable material, that the joining surfaces of the first and second housings (2a, 2b) are formed with a first void and a second void arranged oppositely to and communicating with the first void, wherein the curable material is injected to the first void, and wherein a volume of the curable material is larger than that of the first void and smaller than total of volumes of the first and second voids (37, 38) and that the joining surfaces (35, 36) of the first housing and the second housing have a portion where the housings (2a, 2b) are in direct contact with each other and a portion where the curable material is interposed.