In development of the ceramic breeder blanket, the effective thermal conductivity of pebble beds is an important design parameter. For thermo-mechanical design of blanket, pebble beds were investigated used for Li2TiO3 that was a candidate for tritium breeder. Li2TiO3 pebble beds, whose size was 0.28-1.91 mm diameter, were measured on load under no neutron irradiation. The effective thermal conductivity was increased with load increasing was obtained.