A load switch circuit for turning on and off supply of DC power to a load circuit of a chromatograph apparatus, the load switch circuit comprising: a first switching element connected to between a first node that receives DC voltage and the load circuit, the first switching element including a control terminal that receives a potential of a second node; a capacitive element connected to between the first and second nodes; a first resistive element connected to between the first and second nodes; and a bypass circuit configured to pass current between the first and second nodes upon turn-off of the first switching element.