We have succeeded to fabricate SiC buried gate static induction transistors (BGSITs) with the breakdown voltage VBR of 1270 V at the gate voltage VGS of –12 V and the specific on-resistance RonS of 1.21 mΩ·cm2 at VGS = 2.5 V. The turn-off behaviors of BGSITs strongly depend on the source length WS, which is the distance between the gate electrodes. The rise time tr of BGSIT for WS = 1,070 μm is 395 nsec, while that for WS = 210 μm is 70nsec. From the 3D computer simulations, we confirmed that the difference in turn-off behavior came from the time delay in potential barrier formation in channel region because of high p+ gate resistivity. The turn-off behaviors also depend on the operation temperature, especially for long WS. On the other hand, the turn-on behaviors hardly depend on the WS and temperature.