A sliding assistance device applicable to a slide rail assembly, comprising: a base including a first end portion and a first flexible portion bent from the first end portion, wherein the first flexible portion has a first lateral surface and a second lateral surface, and wherein a first buffer space is defined between the first flexible portion and the first end portion, and one of the first flexible portion and the first end portion has a first protruding section; and wherein the base further includes a second end portion opposite the first end portion and a second flexible portion bent from the second end portion, wherein the second flexible portion has a first lateral surface and a second lateral surface, and a second buffer space is defined between the second flexible portion and the second end portion; one of the second flexible portion and the second end portion has a second protruding section; and wherein the base further includes a third flexible portion bent from the first flexible portion; a third buffer space is defined between the third flexible portion and the first flexible portion; one of the third flexible portion and the first flexible portion has a third protruding section; and wherein the base includes a fourth flexible portion bent from the second flexible portion; a fourth buffer space is defined between the fourth flexible portion and the second flexible portion; one of the fourth flexible portion and the second flexible portion has a fourth protruding section; a plurality of sliding assistance members mounted at the base; wherein when the first flexible portion of the base is subjected to a force, the second lateral surface of the first flexible portion and the first end portion are configured to contact each other through the first protruding section according to the first buffer space; and the second lateral surface of the second flexible portion and the second end portion are configured to contact each other through the second protruding section according to the second buffer space; and the third flexible portion and the first lateral surface of the first flexible portion are configured to contact each other through the third protruding section according to the third buffer space; and the fourth flexible portion and the first lateral surface of the second flexible portion are configured to contact each other through the fourth protruding section according to the fourth buffer space; wherein the sliding assistance members are mounted linearly along the base, with a spacing between each two adjacent sliding assistance members, characterized in that the sliding assistance members are located between the first end portion and the second end portion of the base. a base including a first end portion and a first flexible portion bent from the first end portion, wherein the first flexible portion has a first lateral surface and a second lateral surface, and wherein a first buffer space is defined between the first flexible portion and the first end portion, and one of the first flexible portion and the first end portion has a first protruding section; and wherein the base further includes a second end portion opposite the first end portion and a second flexible portion bent from the second end portion, wherein the second flexible portion has a first lateral surface and a second lateral surface, and a second buffer space is defined between the second flexible portion and the second end portion; one of the second flexible portion and the second end portion has a second protruding section; and wherein the base further includes a third flexible portion bent from the first flexible portion; a third buffer space is defined between the third flexible portion and the first flexible portion; one of the third flexible portion and the first flexible portion has a third protruding section; and wherein the base includes a fourth flexible portion bent from the second flexible portion; a fourth buffer space is defined between the fourth flexible portion and the second flexible portion; one of the fourth flexible portion and the second flexible portion has a fourth protruding section; a plurality of sliding assistance members mounted at the base; wherein when the first flexible portion of the base is subjected to a force, the second lateral surface of the first flexible portion and the first end portion are configured to contact each other through the first protruding section according to the first buffer space; and the second lateral surface of the second flexible portion and the second end portion are configured to contact each other through the second protruding section according to the second buffer space; and the third flexible portion and the first lateral surface of the first flexible portion are configured to contact each other through the third protruding section according to the third buffer space; and the fourth flexible portion and the first lateral surface of the second flexible portion are configured to contact each other through the fourth protruding section according to the fourth buffer space; wherein the sliding assistance members are mounted linearly along the base, with a spacing between each two adjacent sliding assistance members, characterized in that the sliding assistance members are located between the first end portion and the second end portion of the base.