The present study is on a method of the evaluation of physical education classes by students. Some efficient instruments for the summative evaluation have already been developed. However, the reliable instrument for the formative evaluation seems to be missing. Therefore, we intended to develop a convenient and effective instrument for formative evaluation of physical education class which can be used in each teaching unit. The subjects were 1428 pupils from 42 classes in 6 elementary schools. They were asked to answer a questionnaire which contained 28 items on the instructional objectives and the ways of learning after each physical education class in the middle part of the teaching units. Four factors were extracted by means of factor analysis. Those were 1) motivation, 2) outcome, 3) ways of learning, and 4) cooperation. These factors were almost consistent with the standards of evaluation in the guidelines issued by the Japanese Ministry of Education and also with those of the instrument for summative evaluation developed in our previous research. Four factor scores showed significant and positive relationships with those of the comprehensive evaluation items concerning good or effective instruction. Thus, the factors were interpreted as effective standards for formative evaluation. A simplified questionnaire which consisted of 12 items from the 4 factors was constructed as a practical instrument of formative evaluation in elementary school physical education classes.