We have investigated the liquid crystalline behavior and charge carrier transport properties in the semectic phases of a terphenyl derivative, 4-4 ''-bis(dodecyloxy)-3-methyl-p-terphenyl (12O-TPMe-O12) having methyl side chain in the terphenyl core part. In its samples highly purified by recrystallization several times, we observed the transient photocurrents indicating electronic conduction not only for holes but also electrons and determined their mobilities to be 5 x 10(-4) and 0.9 x 10(-2)cm(2)/Vs in SmC and SmG phases, respectively. Thus, we concluded that the intrinsic nature of charge carrier transport in the terphenyl derivatives is electronic and ambipolar, where electrons and holes can be transported.