An acceleration detecting device comprising: a power source; an acceleration sensor that is configured to detect a centrifugal acceleration generated by rotation of a wheel assembly; an acquiring section that is configured to acquire a detection value from the acceleration sensor with a predetermined acquisition period, thereby acquiring the detection value from the acceleration sensor each time the wheel assembly rotates a constant angle; a rotation period calculating section that is configured to calculate a rotation period of the wheel assembly; and an acquisition period setting section that sets the acquisition period, characterized in that the acquisition period setting section is configured to set an acquisition count, which is a number of times the detection value is acquired from the acceleration sensor per rotation of the wheel assembly, in correspondence with the rotation period calculated by the rotation period calculating section so that the acquisition count is increased as the rotation period becomes longer, and calculate the acquisition period by dividing the rotation period by the acquisition count so that the detection value is acquired from the acceleration sensor the number of times corresponding to the set acquisition count during one rotation of the wheel assembly, wherein the acquisition period setting section is further configured to determine whether the rotation period is longer than or equal to a threshold, and set the acquisition count to a greater value when the rotation period is longer than or equal to the threshold than when the rotation period is less than the threshold. a power source; an acceleration sensor that is configured to detect a centrifugal acceleration generated by rotation of a wheel assembly; an acquiring section that is configured to acquire a detection value from the acceleration sensor with a predetermined acquisition period, thereby acquiring the detection value from the acceleration sensor each time the wheel assembly rotates a constant angle; a rotation period calculating section that is configured to calculate a rotation period of the wheel assembly; and an acquisition period setting section that sets the acquisition period, characterized in that the acquisition period setting section is configured to set an acquisition count, which is a number of times the detection value is acquired from the acceleration sensor per rotation of the wheel assembly, in correspondence with the rotation period calculated by the rotation period calculating section so that the acquisition count is increased as the rotation period becomes longer, and calculate the acquisition period by dividing the rotation period by the acquisition count so that the detection value is acquired from the acceleration sensor the number of times corresponding to the set acquisition count during one rotation of the wheel assembly, wherein the acquisition period setting section is further configured to determine whether the rotation period is longer than or equal to a threshold, and set the acquisition count to a greater value when the rotation period is longer set an acquisition count, which is a number of times the detection value is acquired from the acceleration sensor per rotation of the wheel assembly, in correspondence with the rotation period calculated by the rotation period calculating section so that the acquisition count is increased as the rotation period becomes longer, and calculate the acquisition period by dividing the rotation period by the acquisition count so that the detection value is acquired from the acceleration sensor the number of times corresponding to the set acquisition count during one rotation of the wheel assembly