FEED SCREW MECHANISM AND ELECTRIC ACTUATOR

A feed screw mechanism (30) includes: a rotary member (31) having a female screw portion (31a) on an inner peripheral surface; a linear motion member (32) having, on an outer peripheral surface, a male screw portion (32a) that is directly or indirectly screwed to the female screw portion (31a) and making a linear motion with rotation of the rotary member (31); a lubricant housed between the female screw portion (31a) and the male screw portion (32a); a housing (5) that houses the rotary member (31) and the linear motion member (32); and a wall portion (36) protruding, in a radial direction, from the outer peripheral surface of the linear motion member (32). The wall portion (36) makes a linear motion together with the linear motion member (32), and an outer radial end portion of the wall portion (36) is disposed: so as not to contact the inner peripheral surface of the housing (5) and a member provided on the inner peripheral surface of the housing (5); or so as to be slidable with respect to the inner peripheral surface of the housing (5) or the member provided on the inner peripheral surface of the housing (5).