In a method for cultivating cells, there is provided a container (4) comprising an at least partly flexible container wall structure (41). The container is at least resting on a support structure (2). Into the container's interior space (42) there is introduced a gas, a liquid medium (5) and a cell culture. At least part of said support structure together with the container thus resting thereon are being moved, thereby inducing motion to the liquid medium in the container. An upwardly facing outer surface structure of said support structure comprises an elongate downwardly recessed portion (24, 25, 26) which causes a gutter (7) in the container's bottom wall structure (43).