Abstract: This method for raising a platform comprising a platform proper or deck carried by legs bearing on the sea bed comprises: fixing on each of the legs (2) of the platform a raising device (4) constituting a reinforcing device whose regions of fixing to the legs (2) are located on each side of a region of the leg to be cut; cutting the leg so as to divide it into a lower portion (2a) and an upper portion (2b); when all the legs have been cut, actuating the raising devices associated with each of the legs so as to raise the platform to an extent corresponding to the desired raising while controlling the attitude of the platform, and fixing between the ends of the portions (2a) and (2b) of each leg a heightening element (5) which once more interconnects the two portions of the leg, and removing the raising devices.