The invention relates to a method for consolidating soil in a space (10) to be consolidated. In the method, the consolidating agent is fed from a feeding container (9b) into the soil by mixing means (7) arranged in the consolidating agent feeding unit (4). The consolidating agent feeding unit (4) is positioned in connection with the transfer means (1) and the consolidating agent mixing means (7) arranged in the consolidating agent feeding unit (4) are moved by the transfer means (1) optionally at any point in the space (10) to be consolidated in the vertical direction (y), horizontal direction (x) and/or in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction and horizontal direction. The invention also relates to an arrangement for implementing the method.