This study contains the solution of the dark matter mystery of spiral galaxies by using the space of four distance dimensions <i><span>x</span></i><span>, </span><i><span>y</span></i><span>, </span><i><span>z</span></i><span>, </span><i><span>x</span></i><i><span>'</span></i><span "=""><span>, in which </span><i><span>x</span></i></span><i><span>'</span></i><span "=""><span> is the fourth distance dimension. The calculation of galaxy rotation has been presented in the space of four dimensions by using two dimensional section </span><i><span>x</span></i><span>, </span><i><span>x</span></i></span><i><span>'</span></i><span "=""><span> and three dimensional section </span><i><span>x</span></i><span>, </span><i><span>y</span></i><span>, </span><i><span>x</span></i></span><i><span>'</span></i><span "=""><span>. The four dimensional mass </span><i><span>M</span></i><span> which generates the main gravitation field of galaxy is located at the fourth dimension at the distance </span><i><span>x</span></i></span><i><span>'</span></i><span "=""><span> = </span><i><span>X</span></i></span><i><span>'</span></i><span "=""><span> and other dimensions are zero </span><i><span>x</span></i><span> = 0, </span><i><span>y</span></i><span> = 0, </span><i><span>z</span></i><span> = 0. The method to calculate the speed distribution curve of four dimensional mass </span><i><span>V</span><sub><span>M</span></sub></i><span>: the speed distribution curve </span><i><span>V</span><sub><span>M</span></sub> </i><span>is calculated by using the equation in which the gravitational force is equal to the centrifugal force </span></span><span "=""><span>of rotation. The solution of this equation yields the speed distribution</span><span> component </span><i><span>V</span><sub><span>M</span></sub></i><span> of the four dimensional mass </span><i><span>M</span></i><span> and the value of the mass </span><i><span>M.</span></i><span> In the publication </span></span><span>[1]</span><span "=""><span> has been presented rotational speed distributions curv