A insertion/removal apparatus comprises an insertion section with flexibility which is inserted into a target object to perform a desired operation, a shape sensor, an insertion section shape calculator, and a direct manipulation information estimation circuit. The shape sensor detects bending of the insertion section and outputs a detection signal. The insertion section shape calculator which calculates insertion section shape information indicating a shape of the insertion section, based on the detection signal output from the shape sensor. The direct manipulation information estimation circuit which estimates direct manipulation information including at least one of an insertion/removal amount and a rotation amount of the insertion section inserted into and removed from the target object, based on the insertion section shape information.