Coil mounting device and coil mounting method

A coil mounting device includes a stator coil, a coil winding jig that has an outer diameter smaller than an inner diameter of the stator core and winds therearound a belt-shaped coil in an annular shape, a stator core fixing jig that fixes the stator core at a predetermined position and in a predetermined posture, and a coil expansion mechanism that expands the belt-shaped coil. The coil expansion mechanism includes a holder that holds the coil winding jig inside the stator core in a state where the inter-comb-teeth grooves are matched in phase with the slots, and a coil expander that expands the belt-shaped coil by pressing a portion nearer to a side end than the straight portions of the belt-shaped coil wound around the coil winding jig held by the holder so as to expand the portion, thereby inserting the straight portions into the slots.