A fall detection sensor for rammer comprising: an acceleration sensor configured to detect a gravitational acceleration and a motion acceleration with respect to a sensitivity direction, and to output an electrical signal (x, y, z) having a level proportional to a magnitude of the detected acceleration; a low-pass filter configured to remove a frequency component higher than a predetermined frequency from an input signal; an integrator configured to integrate the input signal, and to output an integrated signal (x", y", z") successively; a first comparator configured to compare a value of the input signal with a predetermined threshold, to determine that the rammer has fallen when the value of the input signal is higher or lower than the threshold, and to output a fall detection signal (fs); a second comparator configured to compare a wave pattern of the input signal with a plurality of types of fall sample waves and non-fall sample waves stored in advance, to output a fall detection signal (fs) upon determining that the rammer has fallen when a similarity with the fall sample wave exceeds a predetermined threshold, and to output a non-fall signal (nfs) upon determining that the rammer has not fallen when a similarity with the non-fall sample wave exceeds a predetermined threshold; and control means including a motor stop switch, wherein the fall detection sensor for rammer is configured such that the signal output (x, y, z) from the acceleration sensor is input to the low-pass filter, the signal output (x', y', z') from the low-pass filter is input to the integrator and the second comparator, the signal output (x", y", z") from the integrator is input to the first comparator, and the fall detection signal output (fs) from the first comparator and the fall detection signal (fs) and the non-fall signal (nfs) output from the second comparator are input to the control means, and the fall detection sensor for rammer is configured such that, when the fall detection signal (fs) is output from the first comparator and is input to the control means, and the non-fall signal (nfs) is not input from the second comparator to the control means within a predetermined period after the fall detection signal (fs) is input, and when the fall detection signal (fs) is output from the second comparator and is input to the control means, the motor stop switch operates to stop a motor. an acceleration sensor configured to detect a gravitational acceleration and a motion acceleration with respect to a sensitivity direction, and to output an electrical signal (x, y, z) having a level proportional to a magnitude of the detected acceleration; a low-pass filter configured to remove a frequency component higher than a predetermined frequency from an input signal; an integrator configured to integrate the input signal, and to output an integrated signal (x", y", z") successively; a first comparator configured to compare a value of the input signal with a predetermined threshold, to determine that the rammer has fallen when the value of the input signal is higher or lower than the threshold, and to output a fall detection signal (fs); a second comparator configured to compare a wave pattern of the input signal with a plurality of types of fall sample waves and non-fall sample waves stored in advance, to output a fall detection signal (fs) upon determining that the rammer has fallen when a similarity with the fall sample wave exceeds a predetermined threshold, and to output a non-fall signal (nfs) upon determining that the rammer has not fallen when a similarity with the non-fall sample wave exceeds a predetermined threshold; and control means including a motor stop switch, wherein the fall detection sensor for rammer is configured such that the signal output (x, y, z) from the acceleration sensor is input to the low-pass filter, the signal output (x', y', z') from the low-pass filter is input to the integrator and the second comparator, the signal output (x", y", z") from the integrator is input to the first comparator, and the fall detection signal output (fs) from the first comparator and the fall detection signal (fs) and the non-fall signal (nfs) output from the second comparator are input to the control means, and the fall detection sensor for rammer is configured such that, when the fall detection signal (fs) is output from the first comparator and is input to the control means, and the non-fall signal (nfs) is not input from the second comparator to the control means within a predetermined period after the fall detection signal (fs) is input, and when the fall detection signal (fs) is output from the second comparator and is input to the control means, the motor stop switch operates to stop a motor.