The present invention relates to a bellows-type steam trap that comprises: a steam trap body having an inflow port formed at one side thereof, to which an inflow pipe is connected, and a discharge port formed at the other side thereof, to which a discharge pipe is connected, wherein a channel through which steam passes is formed between the inflow port and the discharge port; and a valve body which is installed in the steam trap body and can expand or contract to open or close the channel.