An angular velocity detection device includes an outer frame including fixed portions, outer beam portions connected to the fixed portions, a sensing part surrounded by the outer frame with first slit therebetween, and a joint connecting the outer frame and the sensing part. The sensing part includes an inner beam portion, a flexible portion, and a detector. The inner beam portion has a hollow region inside and is square-shaped when viewed from above. The flexible portion is formed in the hollow region of the inner beam portion, and is connected to the inner edge of the inner beam portion. The detector is disposed in the flexible portion. The first slit is formed to surround the sensing part excluding the joint.