An electric motor (1) having a mount system (2) is used in particular as a motor for power-assisted steering. The mount system (2) has a roller bearing (8) in the form of a movable bearing, wherein a rolling-surface body (25; 26) of the roller bearing (8) has a groove in which a spring element (18) is arranged. When the electric motor (1) is mounted, the spring element (18) is prestressed in a radial direction (20), with the result that play-free mounting of a shaft (5) of the electric motor (1) is ensured in the radial direction (20) by means of the roller bearing (8).