This invention relates to continuous standing-wave linear electron accelerator (9) comprising a low-energy electron source (10), for example, within a range of 10-20 keV, an accelerating structure (1 or 1′) for accelerating low initial energy electrons to required values; at least, one high-frequency power supply (11) for the said accelerating structure (1 or 1′); a power supply (13) for said electron source (10) and high-frequency power supply (11); a receiving antenna (14), which is arranged in accelerating unit of accelerating structure (1 or 1′) and is used for emitting of high-frequency signal for controlling the amplitude and phase of accelerating field. Low-energy electron beam is directed to the first unit of accelerating structure (1 or 1′) contained successively accelerating units (2, 3, 4i). The first of them is embodied in the form of a bunch resonator (2), the second unit is embodied in the form of a buster resonator (3), and successive units (4i) are used for increasing the electron energy. Also the following is proposed: selection of geometrical parameters of accelerating units, the versions of their arrangement in the said accelerating structure and the use of power supply modes by different high-frequency power sources such as magnetrons, externally excitable klystrons or klystrons operating in a self-oscillating mode with accelerating structure in a feedback circuit.