PURPOSE: To generate an output pulse which has a rise from a base line with a low output resistance value, by realizing a level shift at the base side of an output transistor that is turned on and off in response to the turning-on and -off of a driving transistor.

CONSTITUTION: A diode D1 is connected in series between the collector of a driving transistor TRT1 and the base of an output TRT2, and at the same time a resistance R4 and diodes D2 and D3 are connected in series between the collector and the earth of the TRT2. Then the joint between the R4 and the base of the TRT2 are connected with a diode D4. Furthermore the diodes D5 and D6 are connected to the negative side of the input voltage Vi, and a current is flowed to the D5 and D6 via a resistance R5 to give a level shift to the voltage Vi. When the TRT1 is on, the D1 and the TRT2 are turned off with output voltage V0=0 satisfied. When the TRT1 is off, the D4 is turned off with the TRT2 turned on. Then the prescribed relation is secured between an output resistance R2 and an input resistance R3, V0Vi is satisfied. Thus the amplitude properties of the input/output voltage are equal to a simple function passing through an original point. At the same time, the output resistance value is reduced regardless of the level of the voltage V0. Thus the variance is reduced for the output resistance value.