An absorbent article having a lengthwise direction (L), a lateral direction (W), and a thickness direction (T), the absorbent article comprising: an absorbent core that contains superabsorbent polymer particles, wherein the absorbent core has a skin facing surface , and a non-skin facing surface , and is formed of a skin side layer on a skin facing surface side, and a non-skin side layer on a non-skin facing surface side, the skin side layer includes a plurality of groove portions that extend in the lengthwise direction (L) and penetrate in the thickness direction (T), and a plurality of base portions that extend in the lengthwise direction (L), each of the plurality of groove portions and each of the plurality of base portions alternately extend in the lateral direction (W), the plurality of groove portions include a plurality of main groove portions that extend in the lengthwise direction (L), and a plurality of sub-groove portions that are present in communication with each of the plurality of main groove portions through base ends with predetermined spaces in a direction crossing each of the plurality of main groove portions , the non-skin side layer includes a plurality of groove portion corresponding portions and a plurality of base corresponding portions at positions that overlap the plurality of groove portions and the plurality of base portions in the thickness direction (T), respectively, and a first average density of the superabsorbent polymer particles contained in each of the plurality of groove portion corresponding portions and the plurality of base corresponding portions is lower than a second average density of the superabsorbent polymer particles contained in each of the plurality of base portions . an absorbent core that contains superabsorbent polymer particles, wherein the absorbent core has a skin facing surface , and a non-skin facing surface , and is formed of a skin side layer on a skin facing surface side, and a non-skin side layer on a non-skin facing surface side, the skin side layer includes a plurality of groove portions that extend in the lengthwise direction (L) and penetrate in the thickness direction (T), and a plurality of base portions that extend in the lengthwise direction (L), a plurality of groove portions that extend in the lengthwise direction (L) and penetrate in the thickness direction (T), and a plurality of base portions that extend in the lengthwise direction (L), each of the plurality of groove portions and each of the plurality of base portions alternately extend in the lateral direction (W), the plurality of groove portions include a plurality of main groove portions that extend in the lengthwise direction (L), and a plurality of sub-groove portions that are present in communication with each of the plurality of main groove portions through base ends with predetermined spaces in a direction crossing each of the plurality of main groove portions , a plurality of main groove portions that extend in the lengthwise direction (L), and a plurality of sub-groove portions that are present in communication with each of the plurality of main groove portions through base ends with predetermined spaces in a direction crossing each of the plurality of main groove portions , the non-skin side layer includes a plurality of groove portion corresponding portions and a plurality of base corresponding portions at positions that overlap the plurality of groove portions and the plurality of base portions in the thickness direction (T), respectively, and a first average density of the superabsorbent polymer particles contained in each of the plurality of groove portion corresponding portions and the plurality of base corresponding portions is lower than a second average density of the superabsorbent polymer particles contained in each of the plurality of base portions . <EOS>