A work vehicle comprising: working equipment; and an operating fluid tank having a tank body for collecting operating fluid for driving the working equipment, and a strainer installed inside the tank body; wherein the strainer includes: a cylindrical filter with the axis extending in the vertical direction; a cover member that includes an upper plate part that covers the upper surface of the filter, and a cylindrical part that extends downward from an outer edge part of the upper plate part and covers an upper side surface part of the filter with a gap between the side surface of the filter and the cylindrical part, and allows a lower side surface part of the filter to be exposed; a supporting member having an annular first base part and a first cylinder part that extends upward from an inner circumference edge of the first base part; and an internal cylinder member having a cylindrical shape and being formed with a plurality of through-holes in a side wall, and a lower end part thereof being engaged with the first cylinder part; wherein the filter has a bellows-like shape and is disposed along the outer circumferential surface of the internal cylinder member; wherein the upper plate part has discoid shape, and includes an outer circumference edge part that is folded downward; and wherein at least a portion of an upper end part of the outer circumferential surface of the cylindrical part is fastened to the inner circumferential surface of the outer circumference edge part of the upper plate part. working equipment; and an operating fluid tank having a tank body for collecting operating fluid for driving the working equipment, and a strainer installed inside the tank body; wherein the strainer includes: a cylindrical filter with the axis extending in the vertical direction; a cover member that includes an upper plate part that covers the upper surface of the filter, and a cylindrical part that extends downward from an outer edge part of the upper plate part and covers an upper side surface part of the filter with a gap between the side surface of the filter and the cylindrical part, and allows a lower side surface part of the filter to be exposed; a supporting member having an annular first base part and a first cylinder part that extends upward from an inner circumference edge of the first base part; and an internal cylinder member having a cylindrical shape and being formed with a plurality of through-holes in a side wall, and a lower end part thereof being engaged with the first cylinder part; wherein the filter has a bellows-like shape and is disposed along the outer circumferential surface of the internal cylinder member; wherein the upper plate part has discoid shape, and includes an outer circumference edge part that is folded downward; and wherein at least a portion of an upper end part of the outer circumferential surface of the cylindrical part is fastened to the inner circumferential surface of the outer circumference edge part of the upper plate part. a cylindrical filter with the axis extending in the vertical direction; a cover member that includes an upper plate part that covers the upper surface of the filter, and a cylindrical part that extends downward from an outer edge part of the upper plate part and covers an upper side surface part of the filter with a gap between the side surface of the filter and the cylindrical part, and allows a lower side surface part of the filter to be exposed; a supporting member having an annular first base part and a first cylinder part that extends upward from an inner circumference edge of the first base part; and an internal cylinder member having a cylindrical shape and being formed with a plurality of through-holes in a side wall, and a lower end part thereof being engaged with the first cylinder part; wherein the filter has a bellows-like shape and is disposed along the outer circumferential surface of the internal cylinder member; wherein the upper plate part has discoid shape, and includes an outer circumference edge part that is folded downward; and wherein at least a portion of an upper end part of the outer circumferential surface of the cylindrical part is fastened to the inner circumferential surface of the outer circumference edge part of the upper plate part.