A device for detecting fluid flow, comprising a body having a fluid space that allows fluid to pass therethrough and has a cylindrical inner surface, wherein the body is provided with a fluid supply port that has a supply aperture centered on a central axis of the fluid space and is formed at one end of the fluid space, the body is provided with a fluid discharge port that has a discharge aperture communicating with the fluid space, the body is provided with one electrode (Da) that is made up of a conductor and has a contact exposed at one end of the fluid space, the body is provided with another electrode (Db) that is made up of a conductor, has an exposure part exposed at another end of the fluid space, and is insulated from the one electrode, a valve member made up of a conductor is stored in the fluid space, the valve member being moved along the central axis of the fluid space, coming into contact with the contact of the one electrode (Da) to close the supply aperture, and coming apart from the contact to open the supply aperture, and a coil spring made up of a conductor is stored in the fluid space, the coil spring being connected to the valve member at one end while being connected to the exposure part of the other electrode (Db) at the other end, and always urging the valve member in a direction of closing the supply aperture, wherein the fluid flow is allowed to be detected by electrically sensing connection when the valve member is closed and disconnection when the valve member is opened in an electric circuit that includes the one electrode (Da), the valve member, the coil spring, and the other electrode (Db), characterised in that the body is made up of a conductor, and in that a guide member made up of an insulator is attached onto the valve member, the guide member being formed to secure a flow path of the fluid from the supply aperture to the discharge aperture while being slidable on the cylindrical inner surface of the fluid space, the guide member having a reception surface facing one end face of the fluid space while receiving the fluid from the supply aperture, and having a top surface facing another end face of the fluid space. wherein the body is provided with a fluid supply port that has a supply aperture centered on a central axis of the fluid space and is formed at one end of the fluid space, the body is provided with a fluid discharge port that has a discharge aperture communicating with the fluid space, the body is provided with one electrode (Da) that is made up of a conductor and has a contact exposed at one end of the fluid space, the body is provided with another electrode (Db) that is made up of a conductor, has an exposure part exposed at another end of the fluid space, and is insulated from the one electrode, a valve member made up of a conductor is stored in the fluid space, the valve member being moved along the central axis of the fluid space, coming into contact with the contact of the one electrode (Da) to close the supply aperture, and coming apart from the contact to open the supply aperture, and a coil spring made up of a conductor is stored in the fluid space, the coil spring being connected to the valve member at one end while being connected to the exposure part of the other electrode (Db) at the other end, and always urging the valve member in a direction of closing the supply aperture, wherein the fluid flow is allowed to be detected by electrically sensing connection when the valve member is closed and disconnection when the valve member is opened in an electric circuit that includes the one electrode (Da), the valve member, the coil spring, and the other electrode (Db), characterised in that the body is made up of a conductor, and in that a guide member made up of an insulator is attached onto the valve member, the guide member being formed to secure a flow path of the fluid from the supply aperture to the discharge aperture while being slidable on the cylindrical inner surface of the fluid space, the guide member having a reception surface facing one end face of the fluid space while receiving the fluid from the supply aperture, and having a top surface facing another end face of the fluid space.