How does the group of cells make orientation perpendicular to the flow direction? How does contact with an adjacent cell affect the orientation of the cell? The orientation of a cell according to the neighbor cell under shear flow fields has been traced in vitro. A Couette type flow device with parallel discs was manufactured for the cell culture under the controlled constant wall shear stress. Cells (C2C12: mouse myoblast cell line) were cultured on the lower disc while applying the shear flow in the medium by the upper rotating disc. After culture for 24 hours without flow for adhesion of cells, 2 Pa of the constant wall shear stress was continuously applied in the incubator for 7 days. The behavior of each cell was traced by time-lapse images observed by an inverted phase contrast microscope placed in an incubator. The experiment shows the following results quantitatively by parameters: the contact ratio, and the angle between major axes of cells approximated to ellipsoids. As the ratio of the contact length with the adjacent cell to the pericellular length increases in the two-dimensional projection images, the adjacent cells tend to be oriented in parallel with each other.