A ball pressure gauge for measuring magnitude of an air pressure in an inflatable ball includes: a probe being configured to pierce into the ball; an air-pressure indicator being configured to move according to the magnitude of the air pressure; a gauge body being provided with a set of air-pressure scale for the air-pressure indicator to point and indicate the magnitude of the air pressure as a numeral value; and at least one ball-specific recommended pressure dial being set alongside the air-pressure scale and including segments representing ranges of applicable air pressures for different types of balls. Thereby, the ball pressure gauge informs a user rapidly and directly of ball-specific appropriateness of the measured air pressure, so that the user can instantly adjust the air pressure to optimization.