A device (4) is for connection between a component (2) of an air-conditioning loop (1) and a heat exchanger (3), including at least one channel (6.1, 6.2) through which a fluid (9.1, 9.2) can flow. The device includes an inner part (11) having at least one collar (12.1, 12.2) at least partially defining a channel (10.1, 10.2) and capable of engaging with an opening (6.1, 6.2) of the exchanger (3), and an outer part (15) mounted against the inner part (11), having at least one end piece (16.1, 16.2) at least partially defining the channel (10.1, 10.2) and capable of engaging with an opening of the component (2). The invention also relates to a heat exchanger provided with the connection device (4).