A rack guide unit includes a closure member, a rack guide, and an urging unit. The closure member is secured to an external opening end of an accommodation portion of a housing. The rack guide is accommodated in the accommodation portion so as to be movable in an advancing/withdrawing direction and supports the rack shaft so that the rack shaft is slidable in an axial direction. The urging unit is arranged between the closure member and the rack guide. The urging unit includes a stack of a plurality of coned disc springs urging the rack guide toward the rack shaft and arranged in an identical orientation, and an auxiliary coned disc spring that serves as a holding member holding the stack.