Connection device for electrical or electronic connections. A socket connector with a plurality of contact sockets and a pin connector with a plurality of pin contacts is connected to an electric cable following insertion of the pin connector inside this socket connector. The pin connector has an internally hollow main body which houses a bush inside which these contacts are inserted. The socket connector has an internally hollow main body which houses a second bush and inside which these contact sockets are inserted. The main body of the pin connector is provided with a free section able to engage sealingly inside an annular cavity of this socket connector. A toroidal spring engages grooves in both the socket connector and pin connector to form a snap-type connection therebetween.