To provide a furrow opening blade of a paddy field furrow opener, facilitating removal of sand and earth entering into the furrow opening blade, and facilitating cleaning of the tool used for the removal.

The furrow opening blade 20 includes side plates 21 forming side faces of a furrow, and a bottom plate 23 forming a bottom face of the furrow. The furrow opening blade 20 is provided with a holding tool 40 for holding a mud treating tool 30 for removing the mud entering into the furrow opening blade 20. The holding tool 40 is arranged on the upper surface side of the furrow opening blade 20, and the mud treating tool 30 is detachably held between the right and left side plates 21 of an upper surface side of the furrow opening blade 20.