An intracavitary ultrasound probe of the present invention includes: a housing including: an insertion section having a center axis and a holding section extending in a longitudinal direction of the housing and an ultrasound unit built into the insertion section. The holding section includes: a first axis that matches with the center axis of the insertion section and a second axis that passes through a center of a cross section taken in the vicinity of a longitudinal center of the housing, and extends in parallel to the longitudinal direction. In a cross section perpendicular to the longitudinal direction of the holding section, the first axis is offset from the second axis in an offset direction. In the cross section perpendicular to the longitudinal direction of the holding section, the outer surface of the holding section includes: a first outer surface portion located on a line extending from the second axis in the offset direction and a second outer surface portion located on a line extending from the second axis in a direction opposite to the offset direction. A curvature of the first outer surface portion is smaller than a curvature of the second outer surface portion.
