Scientific psychological and theological approaches to human spirituality are analysed. Principal differences in the interpretation of "knowledge" and "truth" notions in science and religion are shown. The author argues that not every scientific knowledge is connected with spiritual "I". The knowledge becomes spiritual only when it becomes personally meaningful. Four basic directions of spirituality investigation (the looking for spirituality roots in culture; situative and personal factors of spiritual states origin analysis; the studies of spirituality as self-development and self-realization; consideration of spirituality as a divine revelation in Christian psychology) are analysed.