A steam sterilizer (10) for sterilizing instruments and devices, said sterilizer (10) comprising: a container (20) having an inner wall (24) and an outer wall (26), said inner wall (24) defining a sterilization chamber (22), said outer wall (26) being separated from said inner wall (24) to define a cavity (28) surrounding said sterilization chamber (22)； a heating element (46) disposed in a lower part of said cavity (28), said heating element (46) being for vaporizing fluid in said cavity (28)； and a fluid circuit (150) connected to said container (20), said fluid circuit (150) for transporting fluid to said cavity (28), for transporting steam from said cavity (28) to said sterilization chamber (22) and for evacuating steam from said sterilization chamber (22), including said fluid circuit (150): a conduit (182) fluidly connecting said sterilization chamber (22) to said cavity (28), a valve (186) disposed in said conduit (182) to control the flow of steam from said cavity (28) to said sterilization chamber (22), a boiler pump (172) to transport a fluid to said cavity (28) of said container (20)； characterized by: a heat exchanger (174)； a first line (204, 222) for steam draining of said sterilization chamber (22), a portion (222) of said first line (204, 222) extending through said heat exchanger (174)； and a second line (162) fluidly connecting said boiler pump (172) to said cavity (28), a portion of said second line (162) extending through said heat exchanger (174), wherein the Heat is transferred between the vapor of said first line (204, 222) and the fluid of said second line (162).Un esterilizador de vapor (10) para esterilizar instrumentos y dispositivos, constando dicho esterilizador (10) de: un recipiente (20) que tiene una pared interior (24) y una pared exterior (26), definiendo dicha pared interior (24) una cámara de esterilización (22), estando dicha pared exterior (26) separada de dicha pared interior (24) para definir una cavidad (28) que rodea dicha c
