A suction cup unit for gripping workpieces, wherein said suction cup unit comprises a suction cup member carried by a support body, and wherein the support body of the suction cup member also carries a vacuum generating device configured to autonomously generate a vacuum to be applied to the suction cup member, wherein said vacuum generating device includes: - an ejector-effect device, comprising a nozzle configured to generate a vacuum at a nozzle auxiliary outlet when a flow of pressurized air is fed through said nozzle, - at least one electrically-operated valve in the flow of pressurized air to the nozzle, and - a line for connecting said nozzle to said suction cup member, in order to transmit a vacuum to said suction cup member when pressurized air is fed through said nozzle, said suction cup unit being characterized in that: - said support body carrying the suction cup member and the vacuum generating device is in the form of a container, - said suction cup unit includes a reservoir within said container, the reservoir being charged with pressurized air, - said electrically-operated valve is interposed in the connection between the reservoir of pressurized air and the nozzle, for controlling communication between the reservoir and the nozzle, so that an independent vacuum source is provided inside said suction cup unit, without resorting to a suction pump. wherein said vacuum generating device includes: - an ejector-effect device, comprising a nozzle configured to generate a vacuum at a nozzle auxiliary outlet when a flow of pressurized air is fed through said nozzle, - at least one electrically-operated valve in the flow of pressurized air to the nozzle, and - a line for connecting said nozzle to said suction cup member, in order to transmit a vacuum to said suction cup member when pressurized air is fed through said nozzle, - an ejector-effect device, comprising a nozzle configured to generate a vacuum at a nozzle auxiliary outlet when a flow of pressurized air is fed through said nozzle, - at least one electrically-operated valve in the flow of pressurized air to the nozzle, and - a line for connecting said nozzle to said suction cup member, in order to transmit a vacuum to said suction cup member when pressurized air is fed through said nozzle, said suction cup unit being characterized in that: - said support body carrying the suction cup member and the vacuum generating device is in the form of a container, - said suction cup unit includes a reservoir within said container, the reservoir being charged with pressurized air, - said electrically-operated valve is interposed in the connection between the reservoir of pressurized air and the nozzle, for controlling communication between the reservoir and the nozzle, - said support body carrying the suction cup member and the vacuum generating device is in the form of a container, - said suction cup unit includes a reservoir within said container, the reservoir being charged with pressurized air, - said electrically-operated valve is interposed in the connection between the reservoir of pressurized air and the nozzle, for controlling communication between the reservoir and the nozzle, so that an independent vacuum source is provided inside said suction cup unit, without resorting to a suction pump.