Disclosed is a signal transmission circuit device (200) including a feedback signal transmission unit (210) that feeds back a control output signal (Sout) as a feedback signal (Sf) to an input side circuit (200A). A logical comparison circuit (212) detects “mismatch” between input and output by performing logical comparison between a control input signal (Sin) and the feedback signal (Sf). When a state of “mismatch” between input and output occurs, a first pulse generating circuit (202) or a second pulse generating circuit (204) outputs a first correction signal (Sa1) or a second correction signal (Sa2) corresponding to a potential (high level or low level) of the control input signal (Sin), and corrects the control output signal (Sout) to the same potential (high level or low level) as the control input signal (Sin). With such configuration, the mismatch between input and output can be automatically corrected.