A drum brake apparatus includes a housing; a main braking unit installed on one part of the housing, and driven by a hydraulic pressure and pressing a shoe, during main braking; and a parking braking unit installed on the other part of the housing, and driven by an electromotive force of an actuator and pressing the shoe, during parking braking, the parking braking unit includes a bevel gear section disposed in the housing while having a structure of a bevel gear, and rotated in association with the actuator; and a rod section connected with the bevel gear section, and moved out of the housing in association with the bevel gear section and pressing the shoe.