An orientation calculation apparatus includes one or more processors executing instructions in one or more memories to function as an obtaining unit, first and second calculation units, and first and second determination units. The obtaining unit obtains detection signals from a first and second sensor configured to detect movement of a moving apparatus. The first calculation unit calculates first orientation information about the moving apparatus based on an output of the first sensor. The second calculation unit calculates second orientation information about the moving apparatus by a method different from that for the first calculation unit based on the output of the first and second sensor. The first determination unit determines a state of movement of the moving apparatus based on the output of the second sensor. The second determination unit determines an orientation of the moving apparatus based on a result of determination made by the determination unit.