PURPOSE: To obtain a dynamic FF of a reset priority fall set by a small number of elements, by controlling two invertor circuits connected in series, by an MOSFET whose gate is connected to a set or reset terminal.

CONSTITUTION: When an input of a reset terminal R' becomes an L level, FETs 11, 12 become on, an FET15 becomes off, a capacitor 19 is charged, FETs 17, 18 become on, an FET13 becomes off, and an output terminal Q becomes an L level. Accordingly, this FF is reset preferentially irrespective of an input of a set terminal S'. After the reset is released, the terminal Q remains an L level even in case the terminal S' is varied to an H level, but thereafter, when the input of the terminal S' becomes an L level, an FET16 becomes off, an FET14 becomes on, the terminal Q is varied to an H level, and this FF is set.