The present invention relates to a blood circulation assist system that hardly causes complications and does not adversely affect a self-tuning cardiac contraction / dilation function, a control method thereof, and an electrical stimulation device. An electrical stimulation device (100) that outputs an electrical signal that is a pulse wave to at least the lower leg of the human body (P), and an electrocardiographic data acquisition device (200) that continuously acquires an electrocardiographic waveform from the human body (P). And an electrocardiogram data analysis device (300) for analyzing an electrocardiogram waveform acquired by the electrocardiogram data acquisition device (200) and determining an output timing of the electrical signal output from the electrical stimulation device (100). The electrocardiogram data analysis device (300) determines a timing delayed by a predetermined time from the R wave included in the electrocardiographic waveform as the output timing, and the predetermined time is a period of the R wave. This is a time obtained by multiplying the period T by 0.075 to 0.35.合併症を引き起こしにくく、自己調律性の心臓収縮拡張機能に悪影響を与えにくい血液循環補助システム及びその制御方法並びに電気刺激装置に関する。人体（Ｐ）の少なくとも下腿部にパルス波である電気信号を出力する電気刺激装置（１００）と、前記人体（Ｐ）から心電波形を連続的に取得する心電データ取得装置（２００）と、前記心電データ取得装置（２００）が取得した心電波形を解析して、前記電気刺激装置（１００）から出力される前記電気信号の出力タイミングを決定する心電データ解析装置（３００）とを含み、前記心電データ解析装置（３００）は、前記心電波形に含まれるＲ波よりも所定時間遅れたタイミングを前記出力タイミングとして決定し、前記所定時間は前記Ｒ波の周期である周期Ｔに０．０７５～０．３５を乗じた時間である。
