PROBLEM TO BE SOLVED: To provide an absorbent article having improved flexibility in an entire absorber and improved diffusivity of body fluid immediately after excretion.SOLUTION: A diaper 1 includes a surface sheet 2, a backside sheet 3, and a vertically long absorber 4 disposed between both sheets 2 and 3. The absorber 4 has an absorbent core 41. The absorbent core 41 has a block area 410 in which a plurality of block structures are vertically disposed, the block structure consisting of a plurality of protrusions 411 having a high basis weight, disposed on the side of the backside sheet 3, and recessed grooves 412 each of which encloses each protrusion 411, has a low basis weight, and is recessed from the side of the backside sheet 3 towards the side of the surface sheet 2. Parts of the plurality of protrusions 411 have, in the inside of the protrusions 411, high-density protrusion parts 411h each of which comes into contact with the outline of the protrusion 411 and has a relatively high density.
