In a blood-flow-path connector (10) and blood bag system (12), a blocking part (74) is provided in a hollow section (68c) in a tubular body (68), and a communicating part (70) that is axially movable within the hollow section (68c) is disposed. By moving the communicating part (70) relative to the tubular body (68) in a pushing direction, the blocking part (74) is penetrated or pressed to be opened thus, a flow-path in the tubular body (68) and a flow-path in the communicating part (70) come to communicate with each other.
