Abstract: A connection device attached to an outlet end of a pipe of pressurized fluid such as compressed air and used for connecting the pipe to a supply inlet of a utilization device, having an automatically operated valve built therein and arranged to be opened by only pressing it against the inlet of the utilization device to supply the pressurized fluid to the utilization device and closed by only separating it from the inlet of the utilization device to shut off any leakage of the fluid. In the device of this invention, the structure and arrangement of the automatic valve are improved for enabling size reduction of the device. Accordingly, the device of this invention is especially suitable in the case where a plurality of devices are arranged on a single base member and plural pipes connected thereto are automatically connected to and disconnected from corresponding plural utilization devices at the same time.