A dialysate extraction device comprising a dialysate extraction means including an inlet port and an outlet port adapted to be connected to a flow path of fluid for flowing the fluid therethrough and a projected collection port for collecting the fluid flowing through the inlet and outlet port； a outer circumference wall part mounted on the dialysate extraction means so that it covers a projected end of the collection port and is projected therefrom； a connection member formed with a connection portion to be connected to the collection port and a fitting portion to be fitted into an inner circumference of the outer circumference wall part and adapted to extract the fluid through the collection port under a condition in which the connection portion is connected to the outer circumference wall part； and correction portions formed on the inner circumference of the outer circumference wall part for correcting position and attitude of the connection member relative to the collection port before a tip end of the connection member reaches the projected end of the collection port during insertion of the connection member into the outer circumference wall part.
