Interest in sound interfaces is increasing because such interfaces do not need advanced knowledge about particular devices, nor do they require physical operation. However, such interfaces are difficult to use because the general living environment often contains background noise. In order to solve this problem, sound separation systems that use a microphone array sensor have been proposed. In previous work, this microphone array sensor was a small system that considered only two-dimensional (2-D) directivity control. In this paper, we present the design of a spherical microphone array sensor with 3-D directivity. This 3-D directivity property is confirmed via an experimental evaluation.