A fixing-unit roller includes: a core bar; and an elastic layer formed on an outer peripheral surface of the core bar. The elastic layer is formed from a porous material that contains a plurality of cells. Cells in a cross section obtained by cutting across the porous material are 0.1 μm or greater and 50 μm or less in size. A ratio of an area occupied by composite cells, which are made of partially-overlapping spherical cells, in a 200-μm square in the cross section to an area of the square is 60% or greater and 70% or less.