A power conversion device control device comprising a plurality of drive circuits (3UL, 3VL, 3WL, 3UU, 3WU) and a control circuit, each drive circuit including: a semiconductor element drive circuit configured to drive one of a plurality of semiconductor elements (11, 12, 13, 14, 15, 16) of a power conversion device based on a drive signal input from said control circuit; a plurality of protection circuits (51, 52, 53) configured to detect information necessary in order to carry out a protection operation of the semiconductor element; and an alarm signal formation circuit, the alarm signal formation circuit is configured to generate a pulse signal having in one cycle a first constant period (Ta) and a second constant period (Tb) which differs in the signal level from the signal in the first constant period (Ta), wherein the alarm signal formation circuit is configured to set the number of cycles of the pulse signal emitted during a third constant period (tk) to be differerent for each of the plurality of protection circuits (51, 52, 53), wherein the pulse signal is generated continuously during a period in which a first-come first-served protection circuit (51, 52, 53) detects that the protection operation is necessary, wherein the first-come first-served protection circuit is a protection circuit among the plurality of protection circuits (51, 52, 53) which first detects that the protection operation is necessary, the alarm signal formation circuit is further configured such that the alarm signal is not to be generated by other protection circuits (51, 52, 53) during the period in which the first-come first-served protection circuit detects that the protection operation is necessary, and wherein the alarm signal formation circuit is further configured to output as an alarm signal the pulse signal corresponding to the first-come first-served protection circuit to an alarm signal terminal which is connected to the control circuit. a semiconductor element drive circuit configured to drive one of a plurality of semiconductor elements (11, 12, 13, 14, 15, 16) of a power conversion device based on a drive signal input from said control circuit; a plurality of protection circuits (51, 52, 53) configured to detect information necessary in order to carry out a protection operation of the semiconductor element; and an alarm signal formation circuit, the alarm signal formation circuit is configured to generate a pulse signal having in one cycle a first constant period (Ta) and a second constant period (Tb) which differs in the signal level from the signal in the first constant period (Ta), wherein the alarm signal formation circuit is configured to set the number of cycles of the pulse signal emitted during a third constant period (tk) to be differerent for each of the plurality of protection circuits (51, 52, 53), wherein the pulse signal is generated continuously during a period in which a first-come first-served protection circuit (51, 52, 53) detects that the protection operation is necessary, wherein the first-come first-served protection circuit is a protection circuit among the plurality of protection circuits (51, 52, 53) which first detects that the protection operation is necessary, the alarm signal formation circuit is further configured such that the alarm signal is not to be generated by other protection circuits (51, 52, 53) during the period in which the first-come first-served protection circuit detects that the protection operation is necessary, and wherein the alarm signal formation circuit is further configured to output as an alarm signal the pulse signal corresponding to the first-come first-served protection circuit to an alarm signal terminal which is connected to the control circuit.