  Our aim in this paper is to compute the entire cyclic cohomology of
noncommutative 2-tori. First of all, we clarify their algebraic structure of
noncommutative 2-tori as a $F^*$-algebra, according to the idea of
Elliott-Evans. Actually, they are the inductive limit of subhomogeneous
$F^*$-algebras. Using such a result, we compute their entire cyclic cohomology,
which is isomorphic to their periodic one as a complex vector space.
