A column housing for a vehicle steering system is made of synthetic resin and coupled outside a column tube of a steering column for the vehicle system, the column housing including: a slit which is formed to be elongated in a predetermined direction so that the column housing is deformed inward when the column housing is pressed on and fixed to the column tube positioned inside the column housing; and a first reinforcing portion which is formed so as to protrude outward at a predetermined portion from an end position of an end portion of the slit to the periphery of the slit where the slit is not formed, and has a shape having an increased thickness relative to other portions of the column housing.