A calibration method implemented by a computer, includes: measuring, with a laser ranging sensor, markers attached to at least two predetermined positions of a bed portion of a trampoline and calculating coordinates of the markers in a first coordinate system with a position of the laser ranging sensor being an origin; and calculating a conversion parameter to convert coordinates of respective positions of the first coordinate system into coordinates of respective positions of a second coordinate system with a center position of the bed portion being an origin based on a relationship between the calculated coordinates of the markers and the at least two predetermined positions of the bed portion.