The techniques of generating directional spectrum waves have already developed in the towing tank of Yokohama National University. So, many kinds of experiments could be conducted in such waves. Of course the experimental data could also be compared with theoretical results and checked each other. We can find new phenomena in such short crested waves. As one step of these researches, the added resistance experiments were conducted using three models : SR108 (a container ship), SR208 (a tanker), SHSS (a super high speed ship). The mean added resistances were compared with the theoretical calculations which use the conventional Maruo's method. Three models are different shapes and examined in different velocities. Considering their laternal motions (roll motion) and ship bow reflections, we compared the theoretical calculations with the experimental data. Here, all of them will be reported. For the analysis of directional spectrum waves, we adopted MLM (Maximum Likelyhood Method) using the Laser wave surface recorder which was developed recently by ourselves. And the motion transfer functions based on the NSM (New Strip Method) calculations which are checked or modified according to experiments are used. As the results, we got : (1) In the range of short wave length, when the wave directional distribution become wide, the added resistance coefficient seems to be increased both in experiment and theoretical calculation. (2) In the range of short wave length, the wave reflection on the bow can not be reglected. And it can be expressed by Fujii-Takahasi's formula. (3) In directional spectrum waves, the mean added resistances also can be estimated by integrating the accurate added resistance coefficients multiplied by the wave power spectrum. (4) When the ship speed is not so fast, using the response function calculated by NSM method, the added resistances which are calculated by Maruo's theory agree relatively well with the experimental data.