A 300MeV electron linear accelerator has been constructed at Tohoku University. Last May, the first accelerated beam was obtained after four years of construction period, and the accelerator has been operated stably for 2000 hours during the past year. Obtained energy and energy spect-rum of beam is satisfactory and the beam current is reached to the 60% of designed value. Afterthe historical process of construction is described, the general description of the accelerator and some detailed statements of each parts of the accelerator are followed. The beam characteristics are shown in the last section, and the experimental result of nuclear research which was obtained by nsine the 300MeV linacis demonstrated.