Abstract: A transmission device of a hospital bed contains: a main motor, a connection rod unit, a gear unit, and a driver. The gear unit includes a first coupling post, a second coupling post, a first gear, a second gear, a third gear, a third coupling post, and a fourth gear. The driver includes a first case, a second case, a first driving motor, a second driving motor, and a power cable. The first case has a first chamber, a third chamber configured to accommodate the first driving motor, and a fourth chamber configured to accommodate the second driving motor. The second case has a second chamber. The first coupling post, the second coupling post, the first gear, the second gear and the third gear are accommodated in the first chamber. The third coupling post and the fourth gear are accommodated in the second chamber.