Operation device

This operation device is provided with a casing (10), a control substrate accommodated in the casing (10), and a protective cover (2) for protecting the control substrate. The protective cover (2) is provided with a terminal board (3). Further, the protective cover (2) is provided with: a first recessed portion (25) which is positioned at a side opposite to the control substrate side of the protective cover (2), and on the bottom of which the terminal board (3) is provided; a first groove (21) which is, at a +Z direction side end thereof, connected to the outside of the casing (10) via an introduction cutout section (102c) of the casing (10), and a -Z direction side end of which extends toward a side, in the protective cover (2), opposite to the introduction cutout section (102c) side of the casing (10); and a second groove (22) which is connected, at one end (E1) thereof, to the first groove (21) and which is connected, at the other end (E2) thereof, to the first recessed portion (25). The end (E2) of the second groove (22) is disposed at a position closer to an end edge, of the protective cover (2), at the introduction cutout section (102c) side of the casing (10) than the end (E1) of the second groove (22).