An applicator according to one embodiment of the present invention is provided with: a housing that has a cylindrical shape with one closed end, and houses an elastic member and a piston plate that transmits the biasing force of the elastic member to a microneedle； and a releasing means that moves the piston plate along the axial direction of the housing to an opening in the housing by releasing the piston plate, which is engaged in a state of resistance against the biasing force of the elastic member inside the housing. When the engagement of the piston plate is released by the movement of the releasing means to the housing side along the axial direction, the releasing means transmits, to the housing, the force acting in the direction of the opening.本發明提供一種給藥器。本發明之一實施方式之給藥器具備：殼體，其具有一端封閉之筒形狀，並收容有彈性構件及將彈性構件之彈推力傳遞至微針頭之活塞板；及解除機構，其藉由解除在殼體內以抗著彈性構件之彈推力之狀態被卡止之活塞板，而使活塞板沿殼體之軸向朝殼體之開口移動。且在藉由解除機構沿軸向朝殼體側移動而解除活塞板之卡止之際，解除機構將往向開口之方向之力傳遞至殼體。
