Abstract: A fluid pressure control circuit for a working vehicle having a transmission operable by a fluid pressure and a negative type fluid pressure parking brake. The control circuit comprises a fluid pressure cylinder movable to a first end position to place the transmission in a low speed position and to a second end position to place the transmission in a high speed position, a fluid supply line for supplying pressure fluid to the cylinder, and a control valve mounted on the fluid supply line. The control valve comprises a three position valve having a first position to release the pressure fluid from the parking brake and the fluid supply line, a second position to supply the pressure fluid to the parking brake and set the cylinder to the first end position, and a third position to supply the pressure fluid to the parking brake and set the cylinder to the second end position.