Disclosed herein is an oven having guide rails. The oven includes a coking compartment, a shelf member disposed at an inside the cooking compartment and provided such that food substance is mounted, a plurality of guide rails installed such that the shelf member is withdrawn from the cooking compartment, and a fixing wire installed as to connect the plurality of guide rails and having a plurality of contact units configured to make contact with the plurality of guide rails, respectively, and the at least one contact unit is formed while provided with a step. The left and right movements of guide rails may be able to be stabilized by use of the fixing wire stably coupled to the guide rails.