PURPOSE: To minimize an error of total spun length from a set length and an error of a suspension position of roving end from a set suspension position by outputting a suspension order of a frame by a timing which is shorter by roving spun length of inertia and is ahead by a lifting and lowering amount of inertia of a bobbin rail.

CONSTITUTION: In suspension of full bobbins in a roving frame, spun roving length is detected by an encoder 54, inputted to a control device 60 and a frame stopping command is outputted at a timing when the accumulated spun roving length is shorter by precalculated spun length of inertia to minimize an error of the total spun roving length from a set full bobbin length. The spun length of inertia is calculated from a time required from the output of a frame stopping command based on a spinning speed and a spinning state at the speed till the complete suspension of the frame. A frame stopping order is outputted at a timing when the set full bobbin length is ahead by a lifting and lowering amount of a bobbin rail 10 calculated from a time required from the output of a frame stopping command based on a lifting and lowering speed obtained by detecting a lifting and lowering position of the bobbin rail 10 and a spinning state at the speed to complete suspension of the frame minimize an error of a suspension position of roving end from a fixed suspension position.