Segregation patterns of particles of different sizes in a moving bed were theoretically analyzed by a penetration model. Flow experiments with a two-dimensional hopper verified the derived equations in combination with those in the filling of the hopper. The segregating component was revealed to be more unevenly distributed inside the moving bed of wider cone angle at lower feed rate and lower initial mixing ratio as a result of prevalent segregation during heaping on the top of the moving bed. The steeper velocity profile inside the moving bed resulted in a bit more uneven distribution of the segregating component in the angular direction. In general, the segregation profile gradually became smooth during descent of the particle mixture inside the hopper due to particle penetration in the gravitational direction.