EP 3 800 000 A1 the laser beam (L) at one time of irradiation has a waveform including a former portion (100) in which an increase rate of irradiation intensity per unit time is maximized on an outset of irradiation and is gradually reduced as the irradiation intensity approaches a maximum, and a latter portion (104) in which a reduction rate of irradiation intensity per unit time is maximized after the former portion (100) and is gradually reduced as the irradiation intensity approaches a baseline current. irradiating a pluralityoflaserbeams including the laserbeam(S),the plurality oflaserbeams aligned inarow;and irradiating the plurality of laser beams on the surface of the CFRP member at intervals of predetermined time by moving the laser irradiation device (10) in a moving direction orthogonal to the row of the plurality of laser beams, wherein a ratio of a longitudinal interval size to a longest diameter is greater than or equal to 25% and less than or equal to 800%, the longest diameter defined as a moving directional length of each of recesses formed by irradiating the plurality of laser beams, the longitudinal interval size defined as a size of an interval between adjacent two of the recesses in the moving direction. 2. The laser irradiation device (10) according to claim 2, wherein the waveform of the laser beam at one time of irradiation further includes an intermediate portion (102) in which the increase rate of irradiation intensity per unit time approaches zero, the intermediate portion (102) formed between the former portion (100) and the latter portion (104). 3. A surface roughening method of irradiating a laserbeam (L) on a surface of a CFRP member by the laser irradiation device (10) recited in Claim 1 or 2 so as to enhance adhesiveness on the CFRP member. 4. The surface roughening method according to claim 3, further comprising: 7