To obtain a glass fiber reinforce polyamide resin having specified breaking tenacity, excellent mechanical strength, heat resistance and high strength in welded part by containing polyamide resin, and glass fiber in a specific ratio.

This resin manifesting 15-50 kg/mm3/2 of breaking tenacity is obtained by containing (A) the polyamide resin, (B) glass fiber preferably, having 5-25 μm of number average diameter, 250-450 μm of weight average fiber length, compounding in the weight ratio A+B=100 pts.wt. and 40≤A≤90 pts., 10≤B≤60 pts., (C) optionally, adding a heat resistant material, inorganic filler, oxidative deterioration inhibitor, plasticizer, nucleating agent, lubricant, mold-releasing agent, antistatic agent, coloring agents such as pigments, dye, etc. Nylon 66, nylon 6, nylon 6/66, nylon 66/6I (I is isophthalic acid component), etc., are preferably used as the component (A).