PURPOSE: To reduce occurrence of malfunction by bringing a PNP transistor (TR) connected to a collector into continuity stage when the level of the collector level of a switching TR in the nonconductive state starts decreasing at data latch.

CONSTITUTION: When the collector potential of a switching TR Q5 in the discontinuity state starts decreasing due to any cause, since the base potential of an output TR Q3 connecting to the collector of the TR Q5 is decreased, the potential of the output terminal 5 starts decreasing. However, a PNP TR Q31 having the base in common connection to the base of the TR Q3 transfers to the continuity state, and then part of an emitter follower current supplied from a current source 11 starts flowing through the TR Q31. As a result, the emitter current of the TR Q3 is decreased and a voltage drop across the level shift resistor R3 is lessened, so that the base potential of the switching TR Q6 keeping the continuity state is prevented from dropping.