An operation apparatus includes: an operation plate on which an operation surface performed by a pressing operation with an operation body; an assembly member assembled with the operation plate; a first elastic member opposite to the operation surface with respect to the operation plate, and between the operation plate and the assembly member to be elastically deformable by a pressing force applied by the operation body; a sensor detecting an elastic deformation changing amount of the first elastic member generated by the pressing operation; a pressing determinator determining whether the pressing operation is performed based on a detection value of the sensor; and a second elastic member between the operation plate and the assembly member to be elastically deformable with the first elastic member by the pressing force. The first and second elastic members are arranged to enable the pressing force applied serially.