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)
Yeva Milyutina
— Spectator at the concert (uncredited)
Мария Ключарева
— Middle aged woman (uncredited)