PURPOSE: To relieve a defect by providing a switching circuit for relieving defect and a control terminal to a shift register built in a display device or the like to input a control signal to the said terminal thereby disconnecting the defective part of the shift register from a scanning line and a data line.

CONSTITUTION: An input signal to an input terminal 237, for example, is inputted to the shift register 101 via the switcing circuit 201 only when the control signal at the control terminal 238 is at "1". When the control signal is at "0", the input signal does not pass through the switching circuit 201 and the register 101 is stopped. If a defect exists in the register 102, the control signal "0" is impressed to the control terminal 242 and each output terminal is disconnected electrically from the scanning line. Further, in order to avoid an abnormal current caused by the said defect, the control signal "0" is impressed to a control terminal 244 and all input terminals and power terminals of the register 102 are short-circuited.