We study the magnetic (B) field properties in the filamentary molecular cloud associated to N49 bubble. The cloud spanning a length of 16 pc is at a distance of 5 kpc, harboring the N49 mid-infrared (MIR) bubble with a massive ’O’ type star. Near-infrared H-band (1.6 μm) linear polarimetry was carried out using POLICAN instrument. A total of 863 background reddened starlight polarizations were obtained across a 20 x 8 arcmin region. The plane-of-sky (POS) B-field directions inferred from the polarization data reveal a large-scale pattern that is perpendicular to the long-axis of the cloud. The B-field directions near the MIR bubble appear to be curved and pushed along the spherical like morphology of the expanding H II region. This indicates the B-field is frozen into the molecular gas which is compressed by the strong UV radiation from the massive star. The B-field pattern along the length of the cloud shows uniform mean position angle of 136 deg with dispersions less than 20 deg. Estimation of POS B-field strength for multiple sub-regions in the cloud gives a mean value of 6 μG. The mass-to-flux ratio for these regions are found to be magnetically supercritical, implying that gravity dominates B-field. Our results demonstrate that the cloud collapse and fragmentation pre-dominantly occurs along B-field lines.