Operation device having features to assist a user in properly manipulating buttons thereof

摘要

Provided is an operation device to be held by a user with one hand when used. The operation device includes: a recessed portion formed at a position at which at least one of a thumb and fingers is placed when the user holds the operation device; and a main button which is disposed at a bottom of the recessed portion and has a top surface adjacent to a rim portion forming a side surface of the recessed portion.