The paper discusses five instruments made by the organ-builder Johann Frančišek Janeček, who originated from a Bohemian or Moravian family, and who worked in Celje in Slovenia in the 18th century. Five of his preserved organs are embellished with angelic musicians: King David with the harp or St. Cecilia with the organ. The organ cases and figures with musical instruments bear certain resemblances to the work of the Bohemian and Moravian organ-builders. The paper also mentions some characteristics of the organ preserved in the church of Saint Catherine in Prague, made by Martin Janeãek and Jan Storck between 1734 and 1741.