Provided is an electrical connector (3) including an insulative housing (20) defining a number of passageways (202) and a number of contacts (1) received in the corresponding passageways, respectively. Each passageway defines a T-shaped cross-sectional configuration including a narrow fastening slot (2021) and a wide receiving slot (2022) communicated with each other. The contact forms a planar medial section (14) interferingly secured in the fastening slot and a dome-shaped bulge (142) projecting from the planar medial section. A lying wall (2024) adjacent the narrow fastening slot correspondingly defines a recess (2023) to receive the bulge. Therefore, the contact can be securely retained in the passageway and free from disengaging or deflecting from the passageway.