A jet dispersing device includes a high pressure region having a flow inlet and a low pressure region having a flow outlet. A partition wall is positioned within the high pressure region such that the high pressure region is partitioned from the low pressure region. Additionally, the partition wall may be provided with at least one nozzle hole configured to jet a liquid from the high pressure region to the low pressure region such that the liquid is dispersed as fine particles. The partitioning wall may also have a cleaning fluid communication port having an opening area which is larger than an opening area of the at least one nozzle. Additionally, a valve mechanism configured to open and close the cleaning fluid communication port may also be provided.