An input apparatus, a control apparatus, a control system, and a control method that are capable of making a movement of a pointer on a screen a natural movement that matches an intuition of a user are provided. An input apparatus includes a casing, an acceleration sensor, and an angular velocity sensor. The acceleration sensor detects an acceleration value of the casing in a first direction. The angular velocity sensor detects an angular velocity about an axis in a second direction different from the first direction. Instead of calculating a velocity value of the casing by simply integrating the detected acceleration value, the velocity value of the casing in the first direction is calculated based on the acceleration value and the angular velocity value that have been detected. As a result, a highly-accurate calculation of the velocity value of the casing becomes possible, and a movement of a pointer on a screen becomes a natural movement that matches a sense of a user based on a displacement corresponding to the velocity value.