A simple door-folding device comprising a housing for connecting the cabinet body, a mounting element for connecting the cabinet door, and a connecting rod mechanism and an elastic mechanism arranged on the housing, wherein the connecting rod mechanism is movably mounted on the housing to provide an opening and closing action for the cabinet door, wherein the elastic mechanism provides an elastic force for the connecting rod mechanism to automatically open or close the connecting rod mechanism relative to the housing, characterized in that the connecting rod mechanism comprises a first connecting rod, a second connecting rod, a third connecting rod, and a fourth connecting rod, wherein the mounting element is rotatably connected to the front ends of the first connecting rod and the second connecting rod, and wherein the rear ends of the first connecting rod and the second connecting rod are rotatably connected to the front end of the third connecting rod.wherein the middle part of the third connecting rod is rotatably connected to the housing, wherein the rear end of the third connecting rod is provided with a roller, wherein the front end of the fourth connecting rod is rotatably connected to the middle part of the second connecting rod, wherein the rear end of the fourth connecting rod is rotatably connected to the housing, wherein a force arm is arranged between the elastic mechanism and the connecting rod mechanism, wherein one end of the elastic mechanism is rotatably connected to the housing, wherein another end of the elastic mechanism is rotatably connected to the force arm, wherein one end of the force arm is rotatably connected to the housing, wherein the other end of the force arm is provided with a guide block, wherein the roller bears against the side of the guide block so that the roller moves along the side of the guide block when the connecting rod mechanism is automatically opened or closed relative to the housing.