Disclosed embodiments perform readout at a high rate without being affected by transition of pixel transistors. A solid state imaging device of an embodiment has a pixel having a photoelectric conversion unit that generates charges, an amplification transistor including an input node that receives a signal based on the charges generated in the photoelectric conversion unit, and a reset transistor that resets the potential of the input node of the amplification transistor; a signal processing circuit that reads out a signal from the pixel via a signal line; and a switch provided between the signal line and an input node of the signal processing circuit, and a signal value of a control signal applied to the gate of the reset transistor changes while the switch is in the off-state.