PURPOSE: To provide the balloon expanding and launching device with which a balloon is expanded and launched.

CONSTITUTION: An air pump 3 to be driven by a motor 1 is installed and this device is equipped with a ventilation pipe 4 communicating with the air pump 3, spacer 5 fitted to the ventilation pipe 4 for receiving a suction port edge part 6a of a balloon 6, clamper 7 provided with a pawl part 7a for holding the suction port edge part 6a of the balloon 6 with the spacer 5, and slide link 8 for sliding and canceling the holding state of the balloon 6 while bending the clamper 7. Then, the suction port edge part 6a of the balloon 6 is adhered to the spacer 5 and held by the clamper 7, the balloon 6 is expanded by driving the motor, and the balloon 6 is launched by opening the clamper 7 by sliding the slide link 8.