A lifting device for carrying a supported apparatus, wherein the lifting device comprises a driving device (41, 42, 43), a first lever, a second lever, and a plurality of support feet (46, 48); wherein the driving device (41, 42, 43) is adapted to be disposed at the bottom of the supported apparatus; wherein the support feet (46, 48) are adapted to be vertically movably disposed at the bottom of the supported apparatus; wherein a first end of the first lever is pivotally connected to the driving device (41, 42, 43), a second end of the first lever is pivotally connected to one of the support feet (46, 48), and the first lever is adapted to be pivotally connected to the supported apparatus between the first end and the second end thereof; wherein a first end of the second lever is pivotally connected to the driving device (41, 42, 43), a second end of the second lever is pivotally connected to another one of the support feet (46, 48), and the second lever is adapted to be pivotally connected to the supported apparatus between the first end and the second end thereof; wherein the driving device (41, 42, 43)is capable of driving the support feet (46, 48) to move in the vertical direction through the first lever and the second lever in order to raise or lower the supported apparatus; and wherein the distances from the pivotal connection point of the first lever and the second lever with the supported apparatus to the other ends of the first lever and the second lever are set to match each other such that when the driving device (41, 42, 43) drives the first lever and the second lever, the corresponding support feet (46, 48) have the same maximum strokes of the movement in the vertical direction, characterized in that the first lever has a first length, and the second lever has a second length different from the first length. wherein the driving device (41, 42, 43) is adapted to be disposed at the bottom of the supported apparatus; wherein the support feet (46, 48) are adapted to be vertically movably disposed at the bottom of the supported apparatus; wherein a first end of the first lever is pivotally connected to the driving device (41, 42, 43), a second end of the first lever is pivotally connected to one of the support feet (46, 48), and the first lever is adapted to be pivotally connected to the supported apparatus between the first end and the second end thereof; wherein a first end of the second lever is pivotally connected to the driving device (41, 42, 43), a second end of the second lever is pivotally connected to another one of the support feet (46, 48), and the second lever is adapted to be pivotally connected to the supported apparatus between the first end and the second end thereof; wherein the driving device (41, 42, 43)is capable of driving the support feet (46, 48) to move in the vertical direction through the first lever and the second lever in order to raise or lower the supported apparatus; and wherein the distances from the pivotal connection point of the first lever and the second lever with the supported apparatus to the other ends of the first lever and the second lever are set to match each other such that when the driving device (41, 42, 43) drives the first lever and the second lever, the corresponding support feet (46, 48) have the same maximum strokes of the movement in the vertical direction, characterized in that the first lever has a first length, and the second lever has a second length different from the first length.