The temperature dependences (100-380 K) of the dielectric constant and conductivity of a ceramic multiferroic LuFe2O4 with oxygen nonstoichiometry, measured at alternating current (1, 10, 100 kHz, 1 MHz) and in a static electric field (0-7.1 V/mm), are presented. The regularity of the sign inversion of the dynamic permittivity caused by the appearance of solid-state inductance in the samples is discussed. Keywords: negative permittivity, solid-state inductance, multiferroic.