Борис Ливанов

Pyotr Vinogradov, inventor

Valentin Tsishevskiy

Senya Kaufman

Константин Градополов

Kotya Okhotnikov

Galina Pashkova

Valya, music student

Nadezhda Ardi

Tonya, architecture student

Иван Переверзев

Physical education instructor (uncredited)

Татьяна Барышева

Senya's mother (uncredited)

Всеволод Санаев

Red army sailor (uncredited)

Галина Степанова

Young girl (uncredited)

Сергей Антимонов

Professor (uncredited)