Provided are a rotational flow generator, a piping system, a semiconductor manufacturing apparatus, and a heat exchanger that enable the clogging of a pipe member to be more effectively prevented. A rotational flow generator 1 comprises a spray port 14a that can be attached to/removed from a pipe member 103 through which a first fluid flows, and that sprays a second fluid in a direction inclined with respect to the center axis line of the pipe member 103. A rotational flow generated by the rotational flow generator 1 can reduce the amount of accretion on an inner wall of the pipe member 103.

Provided are a rotational flow generator, a piping system, a semiconductor manufacturing apparatus, and a heat exchanger that enable the clogging of a pipe member to be more effectively prevented. A rotational flow generator 1 comprises a spray port 14a that can be attached to/removed from a pipe member 103 through which a first fluid flows, and that sprays a second fluid in a direction inclined with respect to the center axis line of the pipe member 103. A rotational flow generated by the rotational flow generator 1 can reduce the amount of accretion on an inner wall of the pipe member 103.