A liquid administration device comprising: a cylindrically-shaped cylindrical body configured to be filled with liquid in its inside; a needle tube configured to be provided being communicated or communicable with the cylindrical body at the tip side of the cylindrical body, and to have a sharp needle tip at the tip; a gasket configured to be capable of sliding within the cylindrical body; an operation member configured to be provided at the base end side of the gasket and to perform pressing operation to discharge the liquid from the needle tube by pressing the gasket toward the tip direction; a cover member configured to be capable of moving to a first position, in which at least the needle tip of the needle tube is covered, to a second position, moved to the base end direction from the first position, in which the needle tip is exposed, and to a third position, moved to the tip direction from the second position, in which at least the needle tip is re-covered; and a restricting member configured to be capable of restricting movement of the cover member, characterized in that the restricting member is provided with a first engagement part and a second engagement part at different positions from each other, the cover member is provided with a first cover side engagement part with which the first engagement part is capable of being engaged, and a second cover side engagement part with which the first engagement part is capable of being engaged at the base end side compared with the first cover side engagement part, at timing different from the first cover side engagement part, the operation member is provided with an operation part side engagement part with which the second engagement part is capable of being engaged, when the cover member is in the first position, the restricting member is made in a first state where the first engagement part is engaged with the first cover side engagement part, when the cover member has moved from the first position to the second position and the pressing operation by the operation member has been completed, the restricting member moves together with the cover member, while the first engagement part is being engaged with the first cover side engagement part, and is made in a second state where the second engagement part is engaged with the operation part side engagement part, and when the cover member moves from the second position to the third position, the first engagement part is removed from the first cover side engagement part and is engaged with the second cover side engagement part, while the second engagement part is being engaged with the operation part side engagement part, and thus the restricting member is made in a third state where moving back of the cover member to the second position is restricted. a cylindrically-shaped cylindrical body configured to be filled with liquid in its inside; a needle tube configured to be provided being communicated or communicable with the cylindrical body at the tip side of the cylindrical body, and to have a sharp needle tip at the tip; a gasket configured to be capable of sliding within the cylindrical body; an operation member configured to be provided at the base end side of the gasket and to perform pressing operation to discharge the liquid from the needle tube by pressing the gasket toward the tip direction; a cover member configured to be capable of moving to a first position, in which at least the needle tip of the needle tube is covered, to a second position, moved to the base end direction from the first position, in which the needle tip is exposed, and to a third position, moved to the tip direction from the second position, in which at least the needle tip is re-covered; and a restricting member configured to be capable of restricting movement of the cover member, characterized in that the restricting member is provided with a first engagement part and a second engagement part at different positions from each other, the cover member is provided with a first cover side engagement part with which the first engagement part is capable of being engaged, and a second cover side engagement part with which the first engagement part is capable of being engaged at the base end side compared with the first cover side engagement part, at timing different from the first cover side engagement part, the operation member is provided with an operation part side engagement part with which the second engagement part is capable of being engaged, when the cover member is in the first position, the restricting member is made in a first state where the first engagement part is engaged with the first cover side engagement part, when the cover member has moved from the first position to the second position and the pressing operation by the operation member has been completed, the restricting member moves together with the cover member, while the first engagement part is being engaged with the first cover side engagement part, and is made in a second state where the second engagement part is engaged with the operation part side engagement part, and when the cover member moves from the second position to the third position, the first engagement part is removed from the first cover side engagement part and is engaged with the second cover side engagement part, while the second engagement part is being engaged with the operation part side engagement part, and thus the restricting member is made in a third state where moving back of the cover member to the second position is restricted.