The invention relates to the technical field of microbial instruments, and discloses a spin coating device. The spin coating device is used for coating operations of microbial culture. The spin coating device comprises a motor, a tray, a fixed mechanism and a coating bar, wherein the tray is connected with an output shaft of the motor, is used for fixing a culture dish, and is horizontally arranged; the coating bar is fixedly arranged on the fixed mechanism, and the coating end of the coating bar extends into the culture dish. By adopting the technical scheme of the spin coating device, the motor can be used for driving the tray to horizontally rotate, and the coating end of the coating bar which is fixedly arranged on the fixed mechanism extends into the culture dish; when microbial coating needs to be performed, a tester only needs to start the motor, the motor drives the tray to rotate, and the coating bar is used for coating bacterial liquid on a culture medium in the culture dish, so that the automatic coating of microorganisms can be achieved, and the coating efficiency can be greatly increased; in addition, because the culture dish rotates at a constant speed automatically, the tester does not need to coat on the culture medium back and forth by holding the coating bar in a hand, so that the coating uniformity can be increased.