Provided is an operatin mechianism, endoscope apparatus, and guide catheter that enable more intuitive operation of a cuved portion than a rotation input portion, by the use of a tilt input portion. The endoscope apparatus comprises: a rotation input portion provided in an operation section and to which a first drive for for curved operation of a curved portion is input an operation wire connected to the rotation input portion and the curpved portion and which transmits the first drive force to the curved portion by being pulled by the rotation input portion a tilt input portion provided in the operation section and to which a second drive force for curved operation of the curved portion is input and a second transmission means connected to the tilt input portion and the rotation input portion and which transmits the second drive force from the tilt input portion to the rotation input portion. The operation wire transmits the second drive force transmitted from the tilt input unit by the second transmission means to the curved portion.
