Presidents Francois Mitterrand and Mikhail S. Gorbachev discussed on Friday how to improve relations between France and the Soviet Union "in line with a rapidly changing world," the Foreign Ministry said.

Mitterrand arrived Friday for a two-day visit.In their first meetings, he and Gor-bachev spoke of disarmament, reduction of conventional weapons and improving economic ties, according to Foreign Ministry spokesman Gen-nady I. Gerasimov and Hubert Ve-drine, spokesman for Mitterrand.

France has been a harsh critic of Soviet human rights policies, but Ve-drine did not comment on that issue.

Officials announced in connection with the summit that French banks led by Credit Lyonnais are extending a line of credit worth more than $2 billion to the Soviet Union.

Mitterrand will visit the Baikonur Cosmodrome in Soviet Central Asia on Saturday to watch the Soviet-French crew blast off on a trip to the Soviet space station Mir.