To provide a synchronization signal generation circuit generating synchronization signals synchronized with PWM (pulse width modulated) signals from the PWM signals.

A triangular wave generation circuit 101 is a means for generating triangular wave signals in parallel with the generation of triangular wave signals, started in advance each time detecting each of the rising edge and falling edge of the PWM signals PWMIN; changes the triangular wave signals from a reference level with a fixed temporal gradient, after detecting the rising edge or the falling edge; and thereafter changes the triangular wave signals with the temporal gradient of the same size, in the opposite direction after the edge of the same kind is detected. A synchronization signal generating part 160 is a means for generating the synchronization signals SYNC, synchronized with the PWM signals PWMIN, on the basis of the triangular wave signals TRIA, TRIB and TRIC generated by the triangular-wave generating circuit 101, inverts the level of the synchronization signals SYNC, when the size relation of the two triangular wave signals whose generation is started in tandem is reversed, and initializes the triangular wave signals whose generation is started, in advance, to the reference level.