A liquid medication administration device includes a cylindrical body, a gasket, a plunger body that pushes a liquid medication out of the cylindrical body, an advancing mechanism that advances the plunger body, a drive mechanism that drives the advancing mechanism, a chassis member that supports at least the cylindrical body and the advancing mechanism, and a housing that houses the cylindrical body, the plunger body, the advancing mechanism, the drive mechanism, and the chassis member. The chassis member includes a first supporting portion that supports a distal surface of a first supported portion of the cylindrical body and a second supporting portion that supports a proximal surface of a second supported portion of the advancing mechanism.
