A blood circulation system that can be connected to a human body, and transfers removed blood to the human body via a blood transfer pump, the system comprising: the blood transfer pump; a blood removal line through which removed blood flows to the blood transfer pump; a blood transfer line (104, 106) that transfers blood, which is sent from the blood transfer pump, to the human body; blood removal rate measurement means that is provided in the blood removal line; a control unit configured to perform linked control of the blood transfer pump in correspondence with a blood removal rate measured by the blood removal rate measurement means such that a blood transfer rate of the blood transfer pump is in a specific range with respect to the blood removal rate; and blood transfer rate instruction means (160, 170) for instructing a target blood transfer rate of the blood transfer pump in normal control in which the blood transfer pump transfers blood independently from the blood removal rate, wherein the blood transfer rate instruction means includes a blood transfer rate adjustment unit, and wherein the blood transfer rate adjustment unit includes: an operation amount input unit which can adjust the blood transfer rate via a manual operation and outputs a pulse signal according to the input operation amount of the manual operation; and a counter that outputs an amount of the increase and decrease in the transfer rate as a blood transfer rate based on pulse signals output from the operation amount input unit, and the counter outputs the amount of the increase and decrease in the transfer rate as a blood transfer rate with respect to the output value of the operation amount input unit when blood transfer control transitions to the normal control. the blood transfer pump; a blood removal line through which removed blood flows to the blood transfer pump; a blood transfer line (104, 106) that transfers blood, which is sent from the blood transfer pump, to the human body; blood removal rate measurement means that is provided in the blood removal line; a control unit configured to perform linked control of the blood transfer pump in correspondence with a blood removal rate measured by the blood removal rate measurement means such that a blood transfer rate of the blood transfer pump is in a specific range with respect to the blood removal rate; and blood transfer rate instruction means (160, 170) for instructing a target blood transfer rate of the blood transfer pump in normal control in which the blood transfer pump transfers blood independently from the blood removal rate, wherein the blood transfer rate instruction means includes a blood transfer rate adjustment unit, and wherein the blood transfer rate adjustment unit includes: an operation amount input unit which can adjust the blood transfer rate via a manual operation and outputs a pulse signal according to the input operation amount of the manual operation; and a counter that outputs an amount of the increase and decrease in the transfer rate as a blood transfer rate based on pulse signals output from the operation amount input unit, and the counter outputs the amount of the increase and decrease in the transfer rate as a blood transfer rate with respect to the output value of the operation amount input unit when blood transfer control transitions to the normal control.