Provided is a calcium carbonate filler which gives films and the like excellent in moldability, dispersibility, gasmark (bubbles), hue, and further, excellent in optical properties such as reflectivity and light resistance when incorporated into a resin to prepare a resin composition.A calcium carbonate filler for a resin, satisfying the following expressions (a), (b), and (c): 1.0≦Sw≦10.0 (m2/g),  (a) 0.01≦Tw≦0.5(% by weight), and  (b) 80≦Lw≦90  (c) wherein Sw represents a BET specific surface area (m2/g) measured by using a BET specific surface area measuring device (Macsorb manufactured by Mountech Co., Ltd.); Tw represents a weight reduction value (% by weight) measured at 200° C. to 300° C. by using a differential thermogravimetric device (Thermo Plus EVO II manufactured by Rigaku Corporation); and Lw represents a degree of whiteness (L value) measured by using a spectroscopic color-difference meter (ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.).