To provide a focusing device enabling focusing to a focusing position by canceling malfunction in which a focal position is not settled in the vicinity of the focal position in manual focusing.

The focusing device has: a manual operation means 110 for moving a focus lens by manual operation; a calculation means 109 for calculating a focusing signal of the focus lens corresponding to an operation direction and an operation amount by detecting the operation direction and the operation amount of the manual operation means; and a lens drive means 102 for moving the focus lens based on the focusing signal in an optical axis direction. The calculation means finds a differential value of a moving amount of the position of the focus lens equivalent to the operation amount of the manual operation means between change points of the operation direction of the manual operation means, and controls the focusing signal in response to the differential value so as to converge manual focusing operation.