In a mobile soil aerating device comprising a machine frame (36), a drive, at least one penetration tool (30) moved up and down by the drive and being hingedly coupled with the machine frame (36), said penetration tool (30) being adapted to be driven into the soil (28) and to be pulled out again, said penetration tool (30) being pivotable with respect to the machine frame (36) during a penetration phase in which the penetration tool (30) is in the soil (28), said penetration tool (30), prior to penetration, being in an initial position at a predetermined penetration angle, and wherein, at least after having pulled the penetration tool (30) from the ground (28), at least one element engaging the penetration tool (30) and coupled to the machine frame (36) exerts a restoring moment on the penetration tool (30) in order to pivot the penetration tool (30) back to the initial position, it is provided that, at least during a part of the phase in which the penetration tool (30) is in the soil (28), the at least one element engaging the penetration tool (30) exerts a moment on the penetration tool (30) that is opposite to the restoring moment.
