Provided is an electric linear actuator configured so that sliding friction and wear are reduced and so that the electric linear actuator is provided with a rotation prevention mechanism for a screw shaft, the rotation prevention mechanism having a simple configuration and being low in cost. An electric linear actuator is provided with a ball-screw mechanism (8) which converts the rotational motion of an electric motor (3) into the axial rectilinear motion of a drive shaft (7) through a speed reduction mechanism (6). A ridge (21) is formed on the inner periphery of a closed-end hole (9) in a housing (2a). A sleeve (18) is fitted in the closed-end hole (9). The sleeve (18) is formed by press-work from a cold-rolled steel plate having a liquid-phase coating applied thereto. Axially extending grooves (18a) are formed in the sleeve (18) at equal intervals in the circumferential direction so that the sleeve (18) has a petaloid cross-sectional shape. A through-hole (19) extending in the radial direction is formed at an end of a screw shaft (12), and a guide pin (20) is inserted and fitted in the through-hole (19) and engaged with grooves (18a) of the sleeve (18).
