A novel electrooptic switcher is proposed by use of single crystal exhibiting dual transverse Pockels effect, such as lithium niobate crystal. The electrooptic switching operation has been successfully conducted by use of a single lithium niobate crystal with dimensions of 4 mm × 4 mm × 30 mm and four electrodes. In comparison with the conventional crystallised electrooptic switcher, the switching voltage of the above electrooptic switcher decreases from 316 to 225 V.