To provide a drilling mud processing apparatus having a simple configuration capable of efficiently separating particles from excavated mud occurred during boring and thereby obtaining reusable mud with particles having simplified configuration.

A sieving device 112 equipped with multistage screen members 114 and 115 separating mud from particle components which recovers the drilling mud at the time of boring and separates particle components from the mud is provided; and a vibrating device 116 for vibrating screen members 114 and 115 is also installed.The screen members 114 and 115 are made by laminating wire netting with different mesh sizes; in configuration, the separation is performed by increasing the number of times of overshooting of excavated mud and particle components after receiving forces in a direction of applying vibration and in a direction of raising and carrying the drilling mud by the rotating phase of eccentric rotating bodies 121 and 122 installed to the vibrating device 116.