The authors of this paper have observed the distribution of bit patterns property of a binary sequence which is generated by using a primitive polynomial, trace function, and Legendre symbol over the sub extension field. However, one of the most important measure for evaluating the randomness of a sequence which is so called the distribution of bit patterns still has not been investigated. This paper focused on the distribution of bit patterns based on some experimental results. After observing many experimental results, the authors found that the number of appearance of each bit pattern is related to the number of zeros contained in each bit pattern. Furthermore, the authors formulated an equation to explain the distribution of bit patterns in a binary sequence.