An imaging device comprising: a first substrate including: a first pixel (P1) including a first photodiode; a first control line (VMAL) extending along a horizontal direction; a first dummy pixel (P3A) not including a photodiode, the first dummy pixel (P3A) being configured to output a voltage corresponding to a voltage of the first control line (VMAL) in a first period of a blanking period ; and a first signal line (SGL ) extending along a vertical direction coupled to the first pixel (P1) and the first dummy pixel (P3A); and a second substrate stacked on the first substrate including: a first AD converter (ADC ) configured to perform AD conversion on a basis of a voltage of the first signal line (SGL ) in the first period to generate a first digital code, the first AD converter (ADC ) being coupled to the first signal line (SGL ) via a first coupling section ; a signal generator configured to apply a first control signal (VMA) to the first control line (VMAL) via a second coupling section ; and a diagnosis section configured to perform diagnosis processing related to a first signal path including the first coupling section and the second coupling section based on the first digital code through confirming whether or not the first digital code falls within a predetermined range corresponding to a voltage of the first control signal (VMA). a first substrate including: a first pixel (P1) including a first photodiode; a first control line (VMAL) extending along a horizontal direction; a first dummy pixel (P3A) not including a photodiode, the first dummy pixel (P3A) being configured to output a voltage corresponding to a voltage of the first control line (VMAL) in a first period of a blanking period ; and a first signal line (SGL ) extending along a vertical direction coupled to the first pixel (P1) and the first dummy pixel (P3A); and a first pixel (P1) including a first photodiode; a first control line (VMAL) extending along a horizontal direction; a first dummy pixel (P3A) not including a photodiode, the first dummy pixel (P3A) being configured to output a voltage corresponding to a voltage of the first control line (VMAL) in a first period of a blanking period ; and a first signal line (SGL ) extending along a vertical direction coupled to the first pixel (P1) and the first dummy pixel (P3A); and a second substrate stacked on the first substrate including: a first AD converter (ADC ) configured to perform AD conversion on a basis of a voltage of the first signal line (SGL ) in the first period to generate a first digital code, the first AD converter (ADC ) being coupled to the first signal line (SGL ) via a first coupling section ; a signal generator configured to apply a first control signal (VMA) to the first control line (VMAL) via a second coupling section ; and a diagnosis section configured to perform diagnosis processing related to a first signal path including the first coupling section and the second coupling section based on the first digital code through confirming whether or not the first digital code falls within a predetermined range corresponding to a voltage of the first control signal (VMA). a first AD converter (ADC ) configured to perform AD conversion on a basis of a voltage of the first signal line (SGL ) in the first period to generate a first digital code, the first AD converter (ADC ) being coupled to the first signal line (SGL ) via a first coupling section ; a signal generator configured to apply a first control signal (VMA) to the first control line (VMAL) via a second coupling section ; and a diagnosis section configured to perform diagnosis processing related to a first signal path including the first coupling section and the second coupling section based on the first digital code through confirming whether or not the first digital code falls within a predetermined range corresponding to a voltage of the first control signal (VMA). <EOS>