An imaging device comprising: a first substrate including: a first pixel 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 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 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. a first substrate including: a first pixel 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 and the first dummy pixel (P3A); and a first pixel 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 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 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. 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 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.