Crossed cylindrical roller bearing is one kind of bearing whose rollers are square crossing arranged between outer ring and inner ring. The rollers contact the raceway in linearity, so this bearing has better rigidity and less elastic strain. At the same time, this bearing can carry radial load, axial load and moment load simultaneously. They are especially suitable for high rigidity and high running accuracy applications. The dimension of the inner and outer rings is a minimum to miniaturization, especially extremely thin type is close to the limit of small size, and high rigidity, so it is optimal for applications such as joints and swiveling units of industrial robots, swiveling tables of machining centers, rotary units of manipulators, precision rotary tables, medical instrument, measuring instruments, IC manufacturing machines, and etc..