The β + /EC decay of 1 2 6 La produced by the 9 4 Mo( 3 6 Ar, 3pn) reaction has been studied using the on-line isotope separator connected to an AVF cyclotron. Gamma-ray singles, γ-γ angular correlation and internal conversion electron measurements were carried out. From analysis of these data, 33 new levels in 1 2 6 Ba were found and the decay scheme containing 137 γ-rays and 50 excited states was constructed. The probable spin and parity of the two β-decaying states in 1 2 6 La were found to be 4 + /-, 5 + /- for the high-spin isomer with a half-life of 54(2)s and 0 - , 1 + /-, 2 - for the low-spin isomer with a half-life shorter than 50s.