The Lower Thermosphere Profiler Radar (LTPR) at Shigaraki in Shiga Prefecture, Japan (34.86N, 136.11E, 385m MSL) measures ionospheric field-aligned irregularity (FAI) in the E and F-region, which has been operated since 1999. The transmitted center frequency and peak power are 31.57 MHz and 24 kW, respectively. The radar data are used for studies on the morphology of ionospheric irregularities over Japan including the occurrence feature and its daily and seasonal variations. Since the LTPR radar consists of six receiving channels, it is also possible to conduct radar interferometry observations for the study of small-scale structures in the ionospheric irregularities. This radar was also operated at Sakata in Yamagata Prefecture and Tanegashima island in Kagoshima Prefecture for several campaign observations (F- and E- Region Ionosphere Coupling Study:FERIX, 2004, Sporadic E Experiment over Kyushu-2: SEEK-2, July 18, 2003).