A hydraulic control apparatus for a single-acting cylinder, comprising: a switch valve for controlling supply and drainage of a fluid with respect to the cylinder, the switch valve being switched among a supply position for supplying the fluid to the cylinder, a drainage position for draining the fluid from the cylinder, and a neutral position for preventing the supply and the drainage of the fluid with respect to the cylinder; a cylinder line connected to the single-acting cylinder; a switch valve line connected to the switch valve; an adjustment valve arranged between the cylinder line and the switch valve line for selectively connecting and disconnecting the cylinder line and the switch valve line with respect to each other; and a valve control device for controlling operation of the adjustment valve, wherein the adjustment valve includes a fluid chamber, a valve body movably received in the fluid chamber, and a back pressure chamber into which a fluid pressure acting on the valve body is introduced, a restrictor being formed between the valve body and a wall defining the fluid chamber for connecting the cylinder line to the switch valve line, an opening degree of the restrictor being changed in correspondence with movement of the valve body, and wherein, when the switch valve is located at the neutral position or the supply position, the valve control device applies a fluid pressure in the cylinder line to the back pressure chamber for urging the valve body in a direction for disconnecting the cylinder line from the switch valve line, and when the switch valve is located at the drainage position, the valve control device applies a pilot pressure lower than the fluid pressure in the cylinder line to the back pressure chamber, characterized in that the apparatus further includes a connection passage which is different from a path including the adjustment valve and connects the switch valve line to the cylinder line, wherein the connection passage extends between the cylinder line and the switch valve line without passing through the adjustment valve, wherein, when the switch valve is switched to the supply position, the fluid is permitted to flow from the switch valve line to the cylinder line through the connection passage. a switch valve for controlling supply and drainage of a fluid with respect to the cylinder, the switch valve being switched among a supply position for supplying the fluid to the cylinder, a drainage position for draining the fluid from the cylinder, and a neutral position for preventing the supply and the drainage of the fluid with respect to the cylinder; a cylinder line connected to the single-acting cylinder; a switch valve line connected to the switch valve; an adjustment valve arranged between the cylinder line and the switch valve line for selectively connecting and disconnecting the cylinder line and the switch valve line with respect to each other; and a valve control device for controlling operation of the adjustment valve, wherein the adjustment valve includes a fluid chamber, a valve body movably received in the fluid chamber, and a back pressure chamber into which a fluid pressure acting on the valve body is introduced, a restrictor being formed between the valve body and a wall defining the fluid chamber for connecting the cylinder line to the switch valve line, an opening degree of the restrictor being changed in correspondence with movement of the valve body, and wherein, when the switch valve is located at the neutral position or the supply position, the valve control device applies a fluid pressure in the cylinder line to the back pressure chamber for urging the valve body in a direction for disconnecting the cylinder line from the switch valve line, and when the switch valve is located at the drainage position, the valve control device applies a pilot pressure lower than the fluid pressure in the cylinder line to the back pressure chamber, characterized in that the apparatus further includes a connection passage which is different from a path including the adjustment valve and connects the switch valve line to the cylinder line, wherein the connection passage extends between the cylinder line and the switch valve line without passing through the adjustment valve, wherein, when the switch valve is switched to the supply position, the fluid is permitted to flow from the switch valve line to the cylinder line through the connection passage.