The invention provides a backrest device for an apartment bed. A rectangular groove hole is formed in a lower end of a first backrest, two sides of the rectangular groove hole are rotatably connectedwith a rotating shaft, and the rotating shaft is rotatably connected with a cushion; a cushion storage cavity is formed in one side, close to a second backrest, of the first backrest, a telescopic component fixing hole is arranged in the cushion storage cavity, and one side, far away from the second backrest, of the second backrest is fixedly connected with a back cushion; a neck protection pillowis arranged above the back cushion, an upper end of the first backrest is rotatably connected with the upper end of the second backrest through the rotating shaft, a groove is formed in one side, close to the first backrest, of the second backrest, and a telescopic component is rotatably connected in the groove. By arranging the first backrest and the second backrest and fixedly connecting the back cushion and the neck protection pillow at the outsides of the first backrest and the second backrest, the purpose that the bed can be given two people to use simultaneously is reached, and the backrest device is suitable for using in many places such as apartment, dormitory with more people and less space.