A fat-reduction weight-loss method, comprising: firstly, locally heating a site in need of fat-reduction under 37 to 60℃ until the blood and muscles separate from the fat then, locally freezing the site in need of fat-reduction under -10 to 5℃ until the fat solidifies. Also disclosed is a weight-loss instrument using the fat-reduction weight-loss method, comprising: an input unit (A) for receiving a user operation and outputting a signal representing the user operation to a control unit (B) a control unit (B) for outputting a heating signal or a freezing signal to a heating and freezing unit (C) according to the received signal representing the user operation and a heating and freezing unit (C) for receiving the heating signal or freezing signal of the control unit (B) and conducting the heating or freezing operation. The fat-reduction weight-loss method at first locally heats the site in need of fat-reduction to separate the blood and muscles from the fat at the site in need of fat-reduction, then instantaneously freezes the site in need of fat-reduction to solidify the fat, thus avoiding the harms such as tissue necrosis and the like caused by the solidification of the blood and muscles together with the fat in the freezing fat-reduction process.Linvention concerne un procédé de perte de poids par réduction de graisse, consistant à : tout dabord, chauffer localement un site ayant besoin dune réduction de graisse sous 37 à 60°C jusquà ce que le sang et les muscles se séparent de la graisse ensuite, congeler localement le site ayant besoin dune réduction de graisse sous -10 à 5°C jusquà ce que la graisse se solidifie. Linvention concerne également un instrument de perte de poids utilisant le procédé de perte de poids par réduction de graisse, comprenant : une unité dentrée (A) pour recevoir une opération dutilisateur et émettre un signal représentant lopération dutilisateur à une unité de commande (B) une unité de commande (B) pour émettre un signal de chauffage o
