A heat circulation pump includes a pump housing (1) with a pump impeller arranged therein which is arranged in a motor housing (8) which is axially flange-mounted on the pump housing (1). The heat circulation pump also includes a terminal box (12) which is axially connected to the motor housing (8) in order to house electric and/or electronic components of the engine control and for electrically connecting the motor. The terminal box (12) protrudes, radially at least in sections, from the terminal box side end of the motor housing (8) and the terminal box has, in the axial direction, a right-angled outer contour with recesses (20) in the corner areas which are arranged in the axial extension of the screws (11). The flange (10) of the motor housing (8) are fixed to the pump housing (1) by the screws.
