Gas pressure detection device, robot having gas pressure detection device, and gas pressure detection method of the same

A gas pressure detection device 10 detects a decrease in a pressure of gas of a gas balancer 8 of a robot 2. The gas pressure detection device 10 includes a calculating part configured to calculate a parameter Rt(θ) indicating a magnitude relation between a reference pressure Pa(θ) at a rotational angle θ of a rotary arm 14 and a measured pressure Pt(θ) measured at the rotational angle θ, calculate a plurality of parameters Rt(θ) based on a plurality of measured pressures Pt(θ) at different measurement times, and calculate a moving average Rtj(θ) of the parameter Rt(θ) at a measurement time tj that is a j-th measurement time of the measured pressure Pt(θ) (j representing a natural number of 2 or above), and a determining part configured to compare the moving average Rtj(θ) with a reference value R to detect the decrease in the pressure of the gas.