Abstract: The flush toilet bowl includes: a toilet bowl portion; a toilet drainage channel; a toilet bowl main body that includes: a first water discharge port that discharges a first cleaning water that forms a swirling flow; and a second water discharge port that discharges a second cleaning water that is joined, on the downstream side of the first cleaning water flowing on the surface of the toilet bowl portion, by the first cleaning water and forms a downward flow toward the toilet drainage channel; and a toilet bowl cleaning device that supplies the first and second cleaning water, wherein by the time the first cleaning water reaches a merging point where the first cleaning water joins the second cleaning water that forms the downward flow, the second cleaning water has been increased to a set flow rate.