The present invention relates to a washing machine which can close/open a lid on a supplementary washing machine automatically at the time the supplementary washing machine is opened/closed. The washing machine includes a cabinet which forms an exterior of the washing machine, a supplementary washing machine removably mounted to a lower side of the cabinet, having a lid for introducing laundry and a tub for holding the laundry, and an automatic opening/closing member for slidably opening/closing the lid at the time the supplementary washing machine is opened/closed.
