We present a complete apparatus for molecule‐surface interaction studies. Three UHV chambers are connected together allowing preparation, characterization, transfer, and experimental investigations with well‐defined surface samples under ultrahigh‐vacuum conditions. A chopped, supersonic molecular beam with well‐controlled profile enters the main UHV chamber where it is scattered by the sample under study. Detection systems have been designed to measure angular and time‐of‐flight distributions and rotational populations of beam particles scattered off the surface sample giving access to the energy exchange between the internal degrees of freedom of the scattered molecules and the surface. The characteristics of our apparatus are reported and experimental tests for nitrogen and argon molecular beams scattered off a graphite surface are shown.