Provided are a helically traveling carriage and a helically traveling cleaning machine capable of efficiently performing a maintenance process, such as cleaning, with respect to a helical structure formed by winding a helical wall around a column at a central section of a vertically extending cylindrical wall. This helically traveling carriage includes a lower moving-and-contacting part that rolls or slides on a helical wall's upper surface, a lateral bridge mechanism that bridges a column's outer circumferential surface and a cylindrical wall's inner circumferential surface, the lateral bridge mechanism having, on one end thereof, a first moving-and-contacting part that rolls or slides on the cylindrical wall's inner circumferential surface, and having, on the other end, a second moving-and-contacting part that rolls or slides on the column's outer circumferential surface, and a rotary engagement part that rotatably engages with the column by laterally receiving a portion of the column.