a data obtainer that obtains motion data on a motion of an arm of a user that is taking exercise while swinging the arm; and

at least one processor that performs principal component analysis of the motion data obtained by the data obtainer, and obtains, based on a result of performing the principal component analysis, arm-swing type information indicative of a type of arm-swing form of the user, wherein the type of arm-swing form of the user is a type of movement pattern in which the user swings their arm,

wherein:

the data obtainer comprises at least one sensor which detects the motion data in each of a plurality of axis directions,

in obtaining the arm-swing type information, the at least one processor obtains the arm-swing type information based on a level of dispersion of the motion data in each of the axis directions which is obtained by performing the principal component analysis, and

the at least one processor calculates eigenvalues in the respective axis directions, and based on the eigenvalues, the at least one processor calculates an indicator value indicating a straightness and a level of rotation of the arm swing form of the user, as the arm-swing type information.