This paper investigates the Bodhisattva Avalokiteśvara empowerment taught in the Maṇi bka’ ’bum, and is a continuation of my paper published in IBK 69 （2） in 2021, pp. 810-806 and my book entitled Chibetto kenkoku sestuwa to Kanjizai shinkō: Mani Kambum “idainaru rekishisho” wo chūshin ni （チベット建国説話と観自在信仰――『マニ・カンブン』 「偉大なる歴史章」を中心に―― [Urayasu: Kishinshobo, 2021]）, in which I examined the Tibetan term rang sems sangs rgyas （one’s own mind as Buddhahood）, equivalent to zixinfo 自心仏 in Chinese and associated with a path that leads to the fruition of Buddhahood in a single lifetime. Jishinbutsu 自心仏 is a key concept in Japanese esoteric Buddhism, such as that of the Tendai 天台宗 and Shingon schools 真言宗. The concept is derived from the Mahāvairocanasūtra 大日経, a tantric scripture transmitted from India to Tibet during the period of the early diffusion of Buddhism into Tibet （snga dar）. This paper offers a textual source of the Avalokiteśvara empowerment in the Maṇi bka’ ’bum, identified through comparison with research conducted in a monastery belonging to the ’Bri gung Bka’ brgyud school in Ladakh, India, by Taido Kitamura together with other scholars of Shuchiin University, who documented that the empowerment performed in the monastery is based on a text attributed to King Srong btsan sgam po. Kitamura observes that he and his group received an empowerment as taught in the Mahāvairocanasūtra （Kitamura 1982 and 2021）. The numerous identical passages in the Maṇi bka’ ’bum and the description of the empowerment provided by Kitamura indicate that the esoteric teaching taught in the Maṇi bka’ ’bum must be intimately linked with the Mahāvairocanasūtra. The Maṇi bka’ ’bum teaches one’s own mind as being the dharmakāya, the emptiness to be realized through Mahāmudrā. By providing textual sources on the relationship between one’s own mind, Buddhahood and emptiness, this paper contributes to the reconstruction of a history of Tibetan Buddhist thought on Buddha-nature, while also providing a picture of what Buddhism was like during the earlier period of Buddhism in Tibet and identifying who the actual recipients of it were and who later spread it throughout Tibet after the arrival of Atiśa.