Two peculiar types of electronic dispersive structures, irreproducible in bulk band calculations, have been observed in quasi-one-dimensional TlSe studied by angle-resolved photoemission spectroscopy. One is of the cross type centered at the ¥ point and extending along the ¥–H–T direction parallel to the chains, which are formed along the crystallographic c-axis. The other is of the pyramid type with truncated pyramids regularly arranged along the ¥–N direction perpendicular to the chains. To an extent given by the obtained excitation photon energy dependence, the above electronic structures can be assigned to high-lying surface conduction bands resulting from secondary electron emission. Ternary thallium compounds of the formula TlMeX 2 (MeX ¼ TlSe, InSe, GaTe, and InTe) with a quasi-one-dimensional crystal structure have received much attention in relation to their interesting nonlinear electric properties