In a main body of an upper-arm type sphygmomanometer that measures blood pressure of a subject by using a bag-shaped arm cuff to be wound around an arm of the subject, a main body housing includes an upper surface, and a first side surface and a second side surface on left and right sides. The first side surface includes a first side surface electrode region, the second side surface includes a second side surface electrode region, the upper surface includes a first upper surface electrode region, a first electrocardiogram waveform measurement electrode is provided in the first side surface electrode region, a second electrocardiogram waveform measurement electrode is provided in the second side surface electrode region, and a first reference electrode is provided in the first upper surface electrode region.