The present disclosure relates to an apparatus for warning of exceeding speed limit in railway vehicles, wherein a train speed is estimated after a predetermined time, a remaining time is calculated until a train reaches a speed limit based on the estimated speed, and when the calculated time is smaller than a preset reference value, a warning signal is generated. Thus, an adequate warning can be given to cater to a train operation situation because a TTSLC indicator is used that notifies when an emergency braking will be activated by exceeding a set speed limit value after a certain time lapses, resultantly increasing the train operation frequency and the availability of trains.