INCLINATION COMPUTATION DEVICE

An inclination angle calculation device (100) comprises a motion detector (14) for detecting motions of a traveling object during travel, in two directions included in a cross-section surface of the traveling object, the two directions being orthogonal with each other; and an arithmetic unit (15) for calculating an inclination angle of the traveling object during travel in the cross-section surface, using a frequency of the motion in one of the two directions and a rolling frequency in the other direction of the two directions.