PROBLEM TO BE SOLVED: To provide a wash-off type flush toilet capable of maintaining effective filth discharge performance even with a relatively small amount of wash water. The present invention is a wash-off type flush toilet equipped with a bowl portion that receives filth and a drain trap pipeline connected to a lower portion of the bowl portion. The drain trap pipeline consists of an inlet pipe with one end connected to the lower part of the bowl, a trap riser with one end connected to the other end of the inlet to form an ascending flow path, and a trap ascending pipe. It has a trap descending pipe portion in which one end side is connected to the other end side of the portion to form a descending flow path. In the cross section perpendicular to the flow path direction of the ascending flow path, an enlarged portion having a flow path cross-sectional area larger than the flow path cross-sectional area on the upstream side of the ascending flow path is formed in a part of the downstream side of the ascending flow path. There is. At the downstream end of the ascending flow path and / or on the upstream side of the descending flow path, a reduced portion having a flow path cross-sectional area smaller than the flow path cross-sectional area on the upstream side of the ascending flow path is formed. [Selection diagram] Fig. 2
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