Tarski originally took outer Pasch as an axiom. Later, Szmielew chose to take inner Pasch as an axiom instead of outer Pasch. Outer Pasch can be written as the form ∀[∃A→∃B]. In this paper, we can show that outer Pasch itself is equivalent to ∀[∃B→∃A], where ∃B→∃A is the converse of ∃A→∃B, without using the symmetry of the betweenness (SB) or other Tarskian axioms. And then, we show that ∀[∃A↔∃B] is a theorem. Inner Pasch can also be written as the form ∀[∃C→∃D]. But, ∀[∃D→∃C], where ∃D→∃C is the converse of ∃C→∃D, is not true. Of course, ∀[∃C↔∃D] is not a theorem. Thus, we find a property which outer Pasch axiom possesses while inner Pasch axiom does not. The property suggests a reason to prefer to take outer Pasch as an axiom to inner Pasch. In [ 4], Tarski and Givant indicated that the independence of outer Pasch axiom in FG⁽²⁾ is still an open question while by modifying FG⁽²⁾ by replacing Ax.10₁ with Ax. 10₂, then outer Pasch is independent. However, we show that outer Pasch is not independent, specially in FG⁽²⁾ or the modified FG⁽²⁾. For the independence of outer Pasch, we suggest a new version of outer Pasch.