A computer device evaluates an input timing at which a player performed an operation input. The player holds a controller containing sensors for measuring acceleration and angular speed and performs a motion of shaking and stopping the controller. The computer device is communicably connected to the sensors. The computer device determines the input timing by detecting a peak of a measurement value that appears immediately before the stop of the motion. Then, the computer device performs the evaluation based on a difference between the determined input timing and a reference timing.