An immunochromatographic test piece for extracting and measuring a sugar chain antigen in a specimen, the immunochromatographic test piece comprising: a sample pad to which a specimen mixed with nitrite or an acid solution is added; a label region comprising a labeled antibody obtained by labeling an antibody against the sugar chain antigen; and a detection region on which the antibody against the sugar chain antigen is immobilized, wherein an antibody-sugar chain antigen-labeled antibody complex is formed in the detection region to measure the sugar chain antigen, and the immunochromatographic test piece having a region impregnated with a neutralizing reagent upstream of the label region, and further having a region impregnated with a solid acid reagent when the specimen mixed with the nitrite is used, or a region impregnated with nitrite when the specimen mixed with the acid solution is used, upstream of the region impregnated with the neutralizing reagent, wherein a material for the region impregnated with the neutralizing reagent is a woven fabric having a basis weight of 10 to 400 g/m 2 and a thickness of 0.1 to 2.0 mm and having three properties of being highly absorbable, being highly water-retainable, and being low releasable or continuously releasable, wherein the woven fabric absorbs water in an amount of 10 to 100 μl/cm 2 per cm/m 2, has a water absorption speed of 1.0 to 5.0 μl/sec, retains water in an amount of 10 to 100 μl/cm 2 after a fragment of 1 cm/m 2 is allowed to come in a wet state into contact with the detection region and left standing for 5 minutes, and has a liquid spread area of 20 mm 2 or smaller after a fragment of 1 cm/m 2 is allowed to come in a wet state into contact with a membrane and left standing for 5 minutes, and owing to the high water-absorbable property and the high water-retainable property of the region impregnated with the neutralizing reagent, the acid solution containing the sugar chain antigen is sufficiently neutralized, and owing to the low releasable property or the sustained releasable property of the region impregnated with the neutralizing reagent, a remaining acid solution is prevented from arriving at the detection region, or a sufficiently neutralized test solution is continuously developed to the detection region, so that a non-specific reaction is suppressed. a material for the region impregnated with the neutralizing reagent is a woven fabric having a basis weight of 10 to 400 g/m 2 and a thickness of 0.1 to 2.0 mm and having three properties of being highly absorbable, being highly water-retainable, and being low releasable or continuously releasable, wherein the woven fabric absorbs water in an amount of 10 to 100 μl/cm 2 per cm/m 2, has a water absorption speed of 1.0 to 5.0 μl/sec, retains water in an amount of 10 to 100 μl/cm 2 after a fragment of 1 cm/m 2 is allowed to come in a wet state into contact with the detection region and left standing for 5 minutes, and has a liquid spread area of 20 mm 2 or smaller after a fragment of 1 cm/m 2 is allowed to come in a wet state into contact with a membrane and left standing for 5 minutes, and owing to the high water-absorbable property and the high water-retainable property of the region impregnated with the neutralizing reagent, the acid solution containing the sugar chain antigen is sufficiently neutralized, and owing to the low releasable property or the sustained releasable property of the region impregnated with the neutralizing reagent, a remaining acid solution is prevented from arriving at the detection region, or a sufficiently neutralized test solution is continuously developed to the detection region, so that a non-specific reaction is suppressed.