A suitcase, comprising: a back case component; a front lid component; and a ring-shaped gusset component, two opposite sides of the ring-shaped gusset component connected to an edge of the back case component and an edge of the front lid component, respectively, to form an accommodating space, the ring-shaped gusset component comprising a plurality of bending sections and a plurality of sidewall sections which are configured for connecting the plurality of bending sections, the plurality of bending sections disposed on corners of the back case component, respectively, the plurality of sidewall sections disposed on edges of the back case component, respectively, wherein the flexible deformation capability of each of the plurality of bending sections is greater than the flexible deformation capability of each of the plurality of sidewall sections, and the plurality of bending sections are bendable, allowing the plurality of sidewall sections to be folded upward or downward on the back case component, wherein - the front lid component and the ring-shaped gusset component are connected to each other by a connection element, so as to form the accommodating space, wherein the connection element is a zipper, and - the ring-shaped gusset component has a first opening, the front lid component has a second opening, the zipper comprises two chains and a zipper head, the two chains are disposed on an edge of the first opening and an edge of the second opening, respectively, the two chains are connected to each other to form a connection section, wherein the connection section is disposed between the front lid component and the ring-shaped gusset component, the connection section has a length which allows the front lid component and the ring-shaped gusset component to be maintained at a specific distance when the front lid component and the ring-shaped gusset component are separated from each other, and the zipper head is configured for tying the two chains or separating the two chains. a back case component; a front lid component; and a ring-shaped gusset component, two opposite sides of the ring-shaped gusset component connected to an edge of the back case component and an edge of the front lid component, respectively, to form an accommodating space, the ring-shaped gusset component comprising a plurality of bending sections and a plurality of sidewall sections which are configured for connecting the plurality of bending sections, the plurality of bending sections disposed on corners of the back case component, respectively, the plurality of sidewall sections disposed on edges of the back case component, respectively, wherein the flexible deformation capability of each of the plurality of bending sections is greater than the flexible deformation capability of each of the plurality of sidewall sections, and the plurality of bending sections are bendable, allowing the plurality of sidewall sections to be folded upward or downward on the back case component, wherein - the front lid component and the ring-shaped gusset component are connected to each other by a connection element, so as to form the accommodating space, wherein the connection element is a zipper, and - the ring-shaped gusset component has a first opening, the front lid component has a second opening, the zipper comprises two chains and a zipper head, the two chains are disposed on an edge of the first opening and an edge of the second opening, respectively, the two chains are connected to each other to form a connection section, wherein the connection section is disposed between the front lid component and the ring-shaped gusset component, the connection section has a length which allows the front lid component and the ring-shaped gusset component to be maintained at a specific distance when the front lid component and the ring-shaped gusset component are separated from each other, and the zipper head is configured for tying the two chains or separating the two chains. - the front lid component and the ring-shaped gusset component are connected to each other by a connection element, so as to form the accommodating space, wherein the connection element is a zipper, and - the ring-shaped gusset component has a first opening, the front lid component has a second opening, the zipper comprises two chains and a zipper head, the two chains are disposed on an edge of the first opening and an edge of the second opening, respectively, the two chains are connected to each other to form a connection section, wherein the connection section is disposed between the front lid component and the ring-shaped gusset component, the connection section has a length which allows the front lid component and the ring-shaped gusset component to be maintained at a specific distance when the front lid component and the ring-shaped gusset component are separated from each other, and the zipper head is configured for tying the two chains or separating the two chains.