Abstract: The invention relates to a flat solar collector comprising individual vacuum chambers. The invention is formed by two heads and a series of parallel tubes having high transmittance in the solar spectrum, which is disposed between said heads. The opposite side of the heads is provided with vacuum chambers which closure the connections of the conducting tubes. One of the vacuum chambers is characterized in that it is fitted with a vacuum valve at one end thereof. In addition, conducting tubes are disposed inside the aforementioned tubes having high transmittance in the solar spectrum and said conducting tubes are in turn connected to collector plates, all under vacuum conditions which minimize convection energy losses. When the conducting tubes are configured in series, the collector can raise the temperature of the working fluid to above 200° C. All of the above is performed in a novel, simple and economical manner.