A liquid administration device includes: a structure that includes: a cylindrical body including a bottom part in a distal portion and an opening in a proximal portion, a needle tube positioned in the distal portion of the cylindrical body, the needle tube having a sharp needle tip at a distal end, wherein a proximal end of the needle tube is communicatable with the inside of the cylindrical body, and a gasket installed in the cylindrical body, the gasket being slidable in an axial direction of the cylindrical body； an operation member configured to perform a pressing operation by pressing the gasket such that the liquid is discharged from the needle tube； a pressing mechanism configured to generate a pressing force for pressing the gasket； and a pressing force transmission inhibiting mechanism configured to inhibit transmission of the pressing force to the gasket during the pressing operation.
