A medical solution administration device includes a medical solution storage unit configured to store a medical solution a channel part having a channel through which the medical solution is flowable from the medical solution storage unit to a living body a piston a cylinder part having an internal space a driving unit configured to slide the piston between a press end position at which a front end of the piston is located at a first end of the internal space of the cylinder part and a pulled-back position at which the front end of the piston is located at a second end of the internal space of the cylinder part and a seal located at an end of the cylinder part and positioned adjacent to the front end of the piston when the piston is in the pulled-back position, the seal being configured to circumferentially contact the piston.
