Abstract: A pulse receiving circuit constituting a signal transmission device includes a first pulse detector that receives a differential input between a first reception pulse signal, i.e. an internal signal at a secondary winding of a first transformer and a second reception pulse signal, i.e. an internal signal at a secondary winding of a second transformer; a second pulse detector that receives the differential input between the first reception pulse signal and the second reception pulse signal with input polarity reversed to that of the first pulse detector; and a logic unit that generates a reception pulse signal based on output signals of the first and second pulse detectors, respectively.