  We consider the finite temperature Casimir effect of a massive fermionic
field confined between two parallel plates, with MIT bag boundary conditions on
the plates. The background spacetime is $M^{p+1}\times T^q$ which has $q$
dimensions compactified to a torus. On the compact dimensions, the field is
assumed to satisfy periodicity boundary conditions with arbitrary phases. Both
the high temperature and the low temperature expansions of the Casimir free
energy and the force are derived explicitly. It is found that the Casimir force
acting on the plates is always attractive at any temperature regardless of the
boundary conditions assumed on the compact torus. The asymptotic limits of the
Casimir force in the small plate separation limit are also obtained.
