It is intended to provide a transdermal drug administration apparatus having microneedles, which is capable of piercing the skin by a simple procedure in the transdermal administration of a biologically active substance (drug) and allows rapid absorption of the biologically active substance. The present apparatus comprises a microneedle device (50) comprising a microneedle substrate (53) having a plurality of microneedles (51) capable of piercing the skin, an absorbent (11) disposed thereon, the absorbent (11) comprising a material capable of absorbing a liquid, and a dissolving solution reservoir (18) disposed on the absorbent (11), the dissolving solution reservoir (18) containing a dissolving solution (16) for dissolving a drug and being capable of disrupting a diaphragm (20) provided the dissolving solution reservoir (18) and the absorbent (11) by pressing. A coating containing a dry drug is disposed on the microneedles (51) and/or the microneedle substrate (53).
