The BNSR-invariants of a group G are a sequence Σ 1 (G) ⊇ Σ 2 (G) ⊇ · · · of geometric invariants that reveal important information about finiteness properties of certain subgroups of G. We consider the symmetric automorphism group ΣAut n and pure symmetric automorphism group PΣAut n of the free group F n , and inspect their BNSR-invariants. We prove that for n ≥ 2, all the "positive" and "negative" character classes of PΣAut n lie in Σ n−2 (PΣAut n ) \ Σ n−1 (PΣAut n ). We use this to prove that for n ≥ 2, Σ n−2 (ΣAut n ) equals the full character sphere S 0 of ΣAut n but Σ n−1 (ΣAut n ) is empty, so in particular the commutator subgroup ΣAut ′ n is of type F n−2 but not F n−1 . Our techniques involve applying Morse theory to the complex of symmetric marked cactus graphs.