To provide a vegetable fiber-containing organic soil treatment method and device which treat organic soil containing vegetable fiber, such as roots, stalks, and leaves of plants so that the organic soil can be fed by a pump under pressure, and enable the solidification of the organic soil using a filter press.

After removing large lumps from slurry-like organic soil containing dredged or excavated vegetable fibers, the slurry-like organic soil is stored in a separation vessel 1. In the separation vessel 1, separation of soil particles m and the vegetable fiber f is carried out by air bubbling with compressed air, and the vegetable fiber f is made to float in the upper layer part of slurry. The upper layer part of the slurry in which the vegetable fiber is floating is made to overflow to be discharged outside the separation vessel 1, and the slurry from which the vegetable fiber has been removed is pulled out from the separation vessel by a pump 7 to be carried to a dehydration process.