For any symplectic manifold (M, ω), the set of Hamiltonian diffeomorphisms Ham c (M, ω) forms a group and Ham c (M, ω) contains an important subset Aut(M, ω) which consists of time one flows of autonomous(timeindependent) Hamiltonian vector fields on M . One might expect that Aut(M, ω) is a very small subset of Ham c (M, ω). In this paper, we estimate the size of the subset Aut(M, ω) in C ∞ -topology and Hofer's metric which was introduced by Hofer. Polterovich and Shelukhin proved that the complement Ham c \Aut(M, ω) is a dense subset of Ham c (M, ω) in C ∞ -topology and Hofer's metric if (M, ω) is a closed symplectically aspherical manifold where Conley conjecture is established ([10]). In this paper, we generalize above theorem to general closed symplectic manifolds and general convex symplectic manifolds. So, we prove that the set of all non-autonomous Hamiltonian diffeomorphisms Ham c \Aut(M, ω) is a dense subset of Ham c (M, ω) in C ∞ -topology and Hofer's metric if (M, ω) is a closed or convex symplectic manifold without relying on the solution of Conley conjecture.