Stresses to which the propeller shaft of a small diesel ship was subjected under its operating conditions were measured by means of electric resistance strain gauge of foil type. The bending stress was measured on the shaft just forward of the propeller hub, and the torsional and axial stresses were on the aftermost intermediate shaft. The following results were obtained. (1) Amplitude of vibratory bending stress increases with the shaft peed. (2) The first order bending stress which is caused by shifting of thrust centre from the propeller centre, increases with shaft speed. (3) As a result of harmonic analysis of bending stresses, a definite forth order whirling resonance is shown at about 360370 r. p. m., and this coincides to a speed calculated by the Panagopulos' formula. (4) Vibratory combined stress is most affected by vibratory torsional stress and indicates the maximum value at the critical speed of torsional vibration. (5) The stresses measured on the propeller shaft are not so remarkable, but we must consider the effects of stress concentration of key way, fitting of the shaft in propeller hub and corrosion by sea water to fatigue of the shaft.