An applicator according to one embodiment includes a housing having a tubular shape with one closed end, and configured to house an elastic member and a piston plate for transmitting biasing force of the elastic member to the microneedles, and release means configured to release the piston plate engaged in a manner resisting against the biasing force of the elastic member in the housing, to cause the piston plate to move toward an opening of the housing along an axial direction of the housing. The release means is configured, when the release means releases the engagement of the piston plate by moving toward the housing in the axial direction, to transmit force in a direction toward the opening to the housing.