We report the achievement of Bose-Einstein condensation of ytterbium (Yb) atoms by the all-optical method. The Yb atomic beam from an oven is first decelerated by the Zeeman slowing technique using the singlet transition and then captured by a magnetooptical trap using an intercombination transition. The evaporative cooling is performed in a novel crossed optical trap, which results in the formation of condensates of about 5 × 103 atoms of 174Yb. We determine the scattering length of 174Yb to be between 1 and 3 nm by combining the behavior of the condensate and the result of measuring photoassociation. The prospect of Yb condensates is also discussed.