A dose indicator device for a pressurised metered dose inhaler comprising: an inner wheel, an annular outer wheel, an actuator and a housing; the inner wheel comprising a plurality of primary indexing teeth and a flexible drive arm; the annular outer wheel comprising a plurality of secondary indexing teeth on an outer face of the annular outer wheel; the inner wheel and outer annular wheel being located at least partially within the housing such that the inner wheel and annular outer wheel are rotatable about a common longitudinal axis of rotation; the actuator being movable in a plane perpendicular to the longitudinal axis of rotation to engage the primary indexing teeth of the inner wheel to rotate the inner wheel; the housing being fixed relative to the longitudinal axis of rotation and comprising a deflector; the deflector being configured such that, on rotation of the inner wheel, the flexible drive arm is intermittently deflected by the deflector and is thereby brought into contact with the secondary indexing teeth so as to rotate the annular outer wheel about the axis of rotation; wherein the housing further comprises a first flexible restraint which engages the inner wheel to restrain rotation of the inner wheel when not being rotated by the actuator and a second flexible restraint which engages the annular outer wheel to restrain rotation of the annular outer wheel when not being rotated by the inner wheel; and wherein the second flexible restraint is engagable with the secondary indexing teeth of the annular outer wheel; and wherein the actuator is provided on an actuator member, said actuator member being movable by a dispensing container of a pressurised metered dose inhaler into an indexing position on actuation of the pressurised metered dose inhaler to engage the actuator with the primary indexing teeth of the inner wheel to rotate the inner wheel; wherein said actuator member is biased away from the indexing position such that the actuator is disengaged from the primary indexing teeth when the pressurised metered dose inhaler is in a non-dispensing position. an inner wheel, an annular outer wheel, an actuator and a housing; the inner wheel comprising a plurality of primary indexing teeth and a flexible drive arm; the annular outer wheel comprising a plurality of secondary indexing teeth on an outer face of the annular outer wheel; the inner wheel and outer annular wheel being located at least partially within the housing such that the inner wheel and annular outer wheel are rotatable about a common longitudinal axis of rotation; the actuator being movable in a plane perpendicular to the longitudinal axis of rotation to engage the primary indexing teeth of the inner wheel to rotate the inner wheel; the housing being fixed relative to the longitudinal axis of rotation and comprising a deflector; the deflector being configured such that, on rotation of the inner wheel, the flexible drive arm is intermittently deflected by the deflector and is thereby brought into contact with the secondary indexing teeth so as to rotate the annular outer wheel about the axis of rotation; wherein the housing further comprises a first flexible restraint which engages the inner wheel to restrain rotation of the inner wheel when not being rotated by the actuator and a second flexible restraint which engages the annular outer wheel to restrain rotation of the annular outer wheel when not being rotated by the inner wheel; and wherein the second flexible restraint is engagable with the secondary indexing teeth of the annular outer wheel; and wherein the actuator is provided on an actuator member, said actuator member being movable by a dispensing container of a pressurised metered dose inhaler into an indexing position on actuation of the pressurised metered dose inhaler to engage the actuator with the primary indexing teeth of the inner wheel to rotate the inner wheel; wherein said actuator member is biased away from the indexing position such that the actuator is disengaged from the primary indexing teeth when the pressurised metered dose inhaler is in a non-dispensing position.