Abstract: A method for removably implanting a blood filter in a vein of the human body makes use of apparatus that includes an elastic guide wire onto which there can be fitted a semi-rigid tubular mandrel (itself fitted into a thin-walled tubular sheath). A catheter is provided in the form of an easily divisible flexible tube whose distal end permanently bears the blood filter, and whose proximal end is intended to receive a locating member which will be confined under the skin of the patient. After temporary implanting of the filter, a removable strengthening cable can be inserted in a removable manner in the catheter in order to displace the filter along the sheath during its positioning in a vein, in particular in the inferior vena cava of a patient. This filter can be easily removed after a certain period, when the risks of pulmonary embolism are no longer feared.