A coordinate computation device includes a position indication portion, a detection portion, a processor, and a memory. The position indication portion includes an indicating portion, a switch, and a transmitter. The detection portion is configured to detect ultrasonic waves transmitted by the transmitter. The memory is configured to store computer-readable instructions. The computer-readable instructions cause the processor to perform processes that include computing sets of first coordinates, based on times when the detection portion detects the ultrasonic waves, computing a movement direction of the position indication portion on a plane, computing an angle formed between the plane and a direction in which the position indication portion is long, and computing a set of second coordinates, based on the computed movement direction, the computed angle, and a set of third coordinates among the sets of the computed first coordinates.