An end-fire linear tapered slot antenna is presented in the terahertz band. The operation frequency goes from 0.6THz to 2THz, with symmetric radiation patterns from 1THz to 1.7THz and gains up to 15dB. The gaussicity of the beam is over 80% in the whole operation band and efficiency at 1THz of 85%. This antenna gives enough directivity avoiding the use of a typical substrate lens, which introduce 30% of losses. This new design is a good candidate for new applications in the THz range in radio astronomy and Imaging.