An imaging system comprising: an image pickup device in which a plurality of pixels are arranged in two dimensions to generate an imaging signal by performing photoelectric conversion on an optical image of a subject and which is configured to read out the imaging signal generated by the plurality of pixels for each horizontal line; a light source device which includes a light source configured to generate pulsed illumination light with which the subject is irradiated at a timing overlapping with a readout period that is a period in which the imaging signal is read out for the each horizontal line from the image pickup device; and a control unit which is communicably connected to each of the image pickup device and the light source device, the control unit is configured to: control a cycle from a first irradiation start timing to a second irradiation start timing to be shorter than a cycle of each of first and second picture periods by a readout period of one horizontal line, the first irradiation start timing being a timing at which the light source device starts radiating the illumination light in the first picture period in which the image pickup device performs reading, and the second irradiation start timing being a timing at which the light source device starts radiating the illumination light in the second picture period succeeding the first picture period and having the same cycle as the first picture period; characterized in that the control unit is further configured to control the image pickup device and the light source device such that the cycle from the first irradiation start timing to the second irradiation start timing corresponds to a cycle from a start of emission of a first single pulse illuminated period in the first picture period to a start of emission of a second single pulse illuminated period in the second picture period. an image pickup device in which a plurality of pixels are arranged in two dimensions to generate an imaging signal by performing photoelectric conversion on an optical image of a subject and which is configured to read out the imaging signal generated by the plurality of pixels for each horizontal line; a light source device which includes a light source configured to generate pulsed illumination light with which the subject is irradiated at a timing overlapping with a readout period that is a period in which the imaging signal is read out for the each horizontal line from the image pickup device; and a control unit which is communicably connected to each of the image pickup device and the light source device, the control unit is configured to: control a cycle from a first irradiation start timing to a second irradiation start timing to be shorter than a cycle of each of first and second picture periods by a readout period of one horizontal line, the first irradiation start timing being a timing at which the light source device starts radiating the illumination light in the first picture period in which the image pickup device performs reading, and the second irradiation start timing being a timing at which the light source device starts radiating the illumination light in the second picture period succeeding the first picture period and having the same cycle as the first picture period; characterized in that the control unit is further configured to control the image pickup device and the light source device such that the cycle from the first irradiation start timing to the second irradiation start timing corresponds to a cycle from a start of emission of a first single pulse illuminated period in the first picture period to a start of emission of a second single pulse illuminated period in the second picture period. control a cycle from a first irradiation start timing to a second irradiation start timing to be shorter than a cycle of each of first and second picture periods by a readout period of one horizontal line, the first irradiation start timing being a timing at which the light source device starts radiating the illumination light in the first picture period in which the image pickup device performs reading, and the second irradiation start timing being a timing at which the light source device starts radiating the illumination light in the second picture period succeeding the first picture period and having the same cycle as the first picture period; characterized in that the control unit is further configured to control the image pickup device and the light source device such that the cycle from the first irradiation start timing to the second irradiation start timing corresponds to a cycle from a start of emission of a first single pulse illuminated period in the first picture period to a start of emission of a second single pulse illuminated period in the second picture period.