A liquid medication administration device (10) includes a cylindrical body (12), a gasket (34), a plunger body (36) that pushes a liquid medication (M) out of the cylindrical body (12), an advancing mechanism (38) that advances the plunger body (36), a drive mechanism (39) that drives the advancing mechanism (38), a chassis member (24) that supports at least the cylindrical body (12) and the advancing mechanism (38), and a housing (28) that houses the cylindrical body (12), the plunger body (36), the advancing mechanism (38), the drive mechanism (39), and the chassis member (24). The chassis member (24) includes a first supporting portion that supports a distal surface of a first supported portion of the cylindrical body (12) and a second supporting portion that supports a proximal surface of a second supported portion of the advancing mechanism (38).
