NOVELTY - The device (1) has a seat lever including an exercise device lever with an attachment unit e.g. joint screw, for connecting the exercise device lever to the seat lever, where the exercise device lever includes a pivotal joint (22a) on the attachment unit for providing angle flexibility between the seat lever and the exercise device lever to make exercise alteration. A support component provides a releasable elastic force for supporting the exercise device lever. Pedals include a direction adjustable unit for aligning the pedals in parallel or other angles.    USE - Seat mountable exercise device for use in an office during working on a simple desk task. Uses include but are not limited to computer, document, phone talk and study. Can also be used during watching TV and playing videogames.    ADVANTAGE - The device allows convenient installation of support composition on different forms of seat, and provides different alterations of exercises while working, reading or performing sedentary activities simultaneously, thus preventing obesity and promoting public health through promotion of constant movement of the lower body, and stimulating blood circulation for busy sedentary users. The user adjusts the bearing pedal according to the needs and aligns the bearing pedal for exercise alteration functions by controlling the pedal position. The device utilizes a magnetic cycle system that reduces the size of the exercise device body. The device utilizes a spring that allows the exercise device body to repeatedly ascend and descend based on the spring force and pressure applied to a parallelized pedal composition by the user, thus enabling beneficial movement for abdominal exercise, ankle and knee joints, lower back and bowel movement.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a seat mountable exercise device.    Seat mountable exercise device (1)    Seat composition (10)    Exercise device composition (20)    Pivotal joint (22a)    Resistance controller (25)