A flexible tube insertion apparatus (10) includes an insertion section (40), a stiffness variable portion (51), and a detection unit (60). The flexible tube insertion apparatus (10) includes a bend determination portion (121) that determines, based on shape information, whether or not a bent part is present in the insertion section (40), and a control portion (127) that controls a stiffness of the stiffness variable portion (51) provided in a segment arranged in the bent part to be a stiffness that makes the bent part substantially straight, when the bend judgment portion (121) determines that the bent part is present in the insertion section (40).
