[Problem] To provide a liquid medicine administration device whereby transmission loss during transmission of output generated in a motor to a gear or the like can be suppressed. [Solution] The liquid medicine administration device 100 pertaining to the present invention has: an infusion part 11 for infusing a liquid medicine into a living body a liquid medicine storage part 141 for storing a liquid medicine to be sent to the infusion part, the liquid medicine storage part 141 being communicated with the infusion part an extrusion mechanism 143 for moving along the inside of the liquid medicine storage part and delivering the liquid medicine in the liquid medicine storage part to the infusion part in conjunction with the aforementioned movement and a drive mechanism 131 for generating a drive force for moving the extrusion mechanism. The drive mechanism is provided with a motor 136 provided with an output shaft 136a for undergoing rotary motion, a first gear 137a for transmitting the rotation of the output shaft to the extrusion mechanism, and an elastically deformable connecting member 138 for connecting the output shaft and the first gear and thereby causing the first gear to rotate in linkage with the rotation of the output shaft.Linvention fournit un dispositif dadministration de médicament liquide qui permet dinhiber une perte de transmission lors de la transmission dune force de sortie générée par un moteur à un engrenage, ou similaire. Le dispositif dadministration de médicament liquide (100) de linvention possède : une partie injection (11) injectant un médicament liquide dans un corps vivant une partie stockage de médicament liquide (141) communiquant avec la partie injection, et stockant le médicament liquide envoyé dans celle-ci un mécanisme de pression (143) qui se déplace à lintérieur de la partie stockage de médicament liquide, et qui fait partir le médicament liquide contenu à lintérieur de la partie stockage de médicament liquide vers la partie inj
