  We study Ramanujan-Fourier series of certain arithmetic functions of two
variables. We generalize Delange's theorem to the case of arithmetic functions
of two variables and give sufficient conditions for pointwise convergence of
Ramanujan-Fourier series of arithmetic functions of two variables. We also give
several examples which are not obtained by trivial generalizations of results
on Ramanujan-Fourier series of functions of one variable.
