The present invention relates to a wave measurement device loaded on a floatable body. The wave measurement device loaded on a body comprises: an acceleration sensor for measuring the acceleration of a body in the direction of gravity; a water level sensor for measuring the water level of the body; a wave height calculation part for calculating the height of waves based on the acceleration measured by the acceleration sensor and the water level of the body measured by the water level sensor; a buffer memory for accumulating and storing the height of the waves calculated by the wave height calculation part; and a wave data calculation part for calculating at least one among the period and the effective height value of the waves using the accumulated height data of the waves stored in the buffer memory. [Reference numerals] (110) Acceleration sensor; (122) Relative water level measurement part; (130) Water level sensor; (140) Buffer memory; (152) Peak period calculation part; (153) Effective wave height calculation part; (51) First integrator; (52) Second integrator
