An absorbent resin and absorbent composition that use a large amount of material derived from plants, have excellent aqueous liquid absorbing capability, and have excellent absorbing capability in a compressed state due to having a favorable gel elastic modulus. An absorbent resin made by bonding a polysaccharide oxide (A1) having a carboxyl group that may be neutralized by a neutralizing agent, and/or a cross-linked compound thereof (A2), with a poly(meth)acrylic acid (B1) where at least one of the carboxyl groups may be neutralized by a neutralizing agent, and/or a cross-linked compound thereof (B2)； or an absorbent composition made by blending (A1) and/or (A2) and (B1) and/or (B2)； wherein the weight average molecular weight of (A1) is 2000 to 10,000,000, the acid value of (A1) is 65 to 524 mg KOH/g, and if (A1) has a carboxyl group that has been neutralized by a neutralizing agent, the acid value prior to neutralizing is 65 to 524 mg KOH/g.本發明係一種使用較多源自植物之原料，且水性液體之吸收能力優異，由於具有良好之凝膠彈性模數故而加壓狀態下之吸收能力亦優異的吸收性樹脂及吸收性組成物。本發明係一種具有亦可經中和劑中和之羧基之多醣類氧化物(A1)及/或其交聯物(A2)、與至少一個羧基亦可經中和劑中和之聚(甲基)丙烯酸(B1)及/或其交聯物(B2)鍵結而成之吸收性樹脂，或者將上述(A1)及/或(A2)與(B1)及/或(B2)混合而成之吸收性組成物，且上述(A1)之重量平均分子量為2,000~10,000,000，上述(A1)之酸值為65~524mgKOH/g，於上述(A1)具有經中和劑中和之羧基之情形時，中和前之酸值為65~524mgKOH/g。
