To provide an axle load detecting device, which is of comparatively simple construction and which can be manufactured inexpensively without increasing the car weight, for a car with two, rear axles.

An axle load detecting device is provided with a rocking arm 41, whose base end or its vicinity is pivotally supported by a car body 17, which is above and between a rear front axle 11 and a rear rear axle 12, an engaging means, whose both end parts are engaged with the rear front axle 11 and the rear rear axle 12 and whose middle part is engaged with the tip of the rocking arm 41, and a load sensor 42, which is placed at the pivotally locking position of the rocking arm 41 in order to detect the rocked angle of the rocking arm 41. A pulley 43 is provided at the tip of the rocking arm 41. The engaging means, or a wire 44, is engaged with the tip of the rocking arm 41 via a pulley 43, while its both ends are connected to the rear front axle 11 and the rear rear axle 12, respectively.