Structure of support leg member for seat slide device

A structure of support leg member having a pair of reinforcing pieces formed laterally thereof, which is used with a seat slide device provided in an automotive seat, wherein an inclinable portion is defined in the upper securing portion of the support leg member on which a guide rail of the seat slide device is securely amounted. The inclinable portion allows the guide rail to be inclined by a great load applied thereto in excess of a tolerable amount, thereby protecting the seat slide device against damage. The inclinable portion, for instance, may comprise an upward protuberant bead formed in the upper securing portion so that a pair of spadngs are defined between the guide rail and a base portion of that upper securing portion such as to allow inclination of the guide towards the center of the automotive seat. Alternatively, the inclinable portion may be embodied by bending one or both of the two reinforcing pieces outwardly to render the support leg member so less rigid as to be buckled slantwise by the foregoing great load, thereby allowing inclination of the guide rail towards the center of the automotive seat.