EXTRAVASCULAR LEAK DETECTING DEVICE, AND TRANSFUSION DEVICE

PROBLEM TO BE SOLVED: To provide an extravascular leak detecting device for detecting the risk of leaking a chemical, which is caused when an endovascular indwelling catheter, etc., comes off a blood vessel to tissue, and also to provide a transfusion device.SOLUTION: The extravascular leak detecting device 1 includes; an endovascular indwelling catheter or an indwelling needle 5 where a distal end opening 5B is indwelled inside the blood vessel 100 and a hole 30 for generating sound when passing the chemical is formed; a receiving part 20 for generating a reception signal G by detecting bloodstream noise sound N which is generated in the hole 30 when the chemical W passes the endovascular indwelling catheter or the indwelling needle 5; and a control part for determining that the distal end opening 5B of the endovascular indwelling catheter or the indwelling needle is positioned inside the blood vessel 100 in a state where the reception signal is being generated by the receiving part 20 in response to the bloodstream noise sound, and determines that the distal end 5B of the endovascular indwelling catheter or the indwelling needle comes off the blood vessel 100 so as to leak the chemical W to the outer part of the blood vessel 100 in a state where the reception signal other than the bloodstream noise sound is being generated by the receiving part 20.