This study specifies the main factors which may influence evaluation of L2 speaking by Japanese Teachers of English (JTEs) and ones which may influence Assistant English Teachers' (AETs'). 18 objective quantifiable variables (called performance variables in this paper) obtained from text analysis of transcriptions of examinees' speech and a subjective quantifiable variable obtained from holistic evaluation by JTEs and AETs were prepared. Multi Regression Analysis was conducted with the 18 objective variables as independent variables and with the subjective variable as a dependent variable. The result showed in both JTEs' and AETs' evaluation of L2 speaking that speech rate seemed the most significant factor affecting ratings (r=0.61 in JTEs' and r=0.57 in AETs') and that the number of local errors appeared the second most significant factor (r=-0.55, r=-0.50 respectively). The same factors seemed to primarily affect evaluation in both JTEs' ratings and AETs'; prominent differences between JTEs' and AETs' ratings could not be discovered in the present experiment.