In a distance measurement device of an embodiment, a light source emits modulation light in a first charge transfer cycle, and emission of the modulation light of the light source is stopped in a second charge transfer cycle. In each of the first and second charge transfer cycles, the charges generated in a photosensitive region are distributed to a first accumulation region and a second accumulation region. A first value is obtained based on readout values corresponding to amounts of accumulated charges of the first accumulation region. A second value is obtained based on readout values corresponding to amounts of accumulated charges of the second accumulation region. A distance is calculated based on the first value and the second value.