KEK-TRISTAN. Measurement of forward-backward charge asymmetry in b-quark production in e+ e- annihilation in the cm energy range 50 to 64 GeV by the VENUS Collaboration. b-quarks are identified from electrons and muons from their semileptonic decays. Data come from a sample of 5947 multihadron events for the electron analysis and 5627 events from the muon analysis. The integrated luminosity is 65.3 pb-1 and 60.8 pb-1 respectively.