A transdermal administration device comprising: a substrate having a first surface ; and a plurality of projections extending from the first surface , each projection including a columnar portion having a columnar shape extending from the first surface and a tapered portion having a tapered shape extending from a top of the columnar portion , wherein in each of the plurality of projections , a maximum angle (θ) of an apex of the tapered portion as viewed in a direction parallel with the first surface is in a range of 10° or more and 30° or less, and a ratio of a taper length (L3) to a projection length (L1) is in a range of 0.45 or more and 0.75 or less, wherein the projection length (L1) is a length from a proximal end to a distal end of the projection in a direction perpendicular to the first surface , and the taper length (L3) is a length of from a proximal end to a distal end of the tapered portion in a direction perpendicular to the first surface , characterized in that a pitch (P), which is a distance between a center (C) of one of the projections and a center (C) of another projection closest to the one of the projections , is in a range of 50 μm or more and 350 μm or less, wherein the center (C) of the projection is a center of gravity of a shape of an outline of the projection as viewed in a direction perpendicular to the first surface , and a portion of the projection which includes the distal end constitutes a first layer (R1) which is made of a first material, and a portion of the projection which includes the proximal end and the substrate constitute a second layer (R2) which is made of a second material. a substrate having a first surface ; and a plurality of projections extending from the first surface , each projection including a columnar portion having a columnar shape extending from the first surface and a tapered portion having a tapered shape extending from a top of the columnar portion , wherein in each of the plurality of projections , a maximum angle (θ) of an apex of the tapered portion as viewed in a direction parallel with the first surface is in a range of 10° or more and 30° or less, and a ratio of a taper length (L3) to a projection length (L1) is in a range of 0.45 or more and 0.75 or less, wherein the projection length (L1) is a length from a proximal end to a distal end of the projection in a direction perpendicular to the first surface , and the taper length (L3) is a length of from a proximal end to a distal end of the tapered portion in a direction perpendicular to the first surface , characterized in that a pitch (P), which is a distance between a center (C) of one of the projections and a center (C) of another projection closest to the one of the projections , is in a range of 50 μm or more and 350 μm or less, wherein the center (C) of the projection is a center of gravity of a shape of an outline of the projection as viewed in a direction perpendicular to the first surface , and a portion of the projection which includes the distal end constitutes a first layer (R1) which is made of a first material, and a portion of the projection which includes the proximal end and the substrate constitute a second layer (R2) which is made of a second material. <EOS>