Soil treatment device for treating a contaminated soil and/or groundwater contained therein, comprising measuring means for measuring contamination of the soil, injecting means for injecting soil decontamination agents in the soil and a longitudinal soil penetration rod provided with a rod tip at an end of the soil penetration rod for moving the soil penetration rod into the soil, the outer surface of the soil penetration rod comprising a measuring section comprising at least one sensor of the measuring means for measuring contamination of the soil adjacent to the measuring section when moved into the soil and an injection section comprising at least one injection nozzle of the injecting means for injecting decontamination agent in the soil adjacent to the injection section, wherein the measuring section and the injection section are provided at longitudinally distinct locations of the soil penetration rod and in that the measuring section is closer to the rod tip than the injection section, characterized in that the distance between the injection section and the measuring section is at least 0.5 m.