A protective cap (201, 501) comprising: a cap body (203, 507) formed in a bowl form, an opening portion of the cap body being substantially horizontal and the opening portion being positioned at a slightly upper side than the wearer's ears when a standing upright wearer wears the protective cap; a guide member (211, 509) comprising an arc-like guide portion (213, 523), the guide member (211, 509) being so formed in the interior of the bowl form of the cap body (203, 507) and integrally with the cap body (203, 507) that a pivotal center of the guide portion (213, 523) corresponds with an axis (C201, C501) extending in left and right directions through a portion at the rear of ears of the wearer of the cap body (203, 507); and a shield plate (205, 503) formed in a plate form of a transparent material or a translucent material, the shield plate (205, 503) comprising an engagement portion (215, 525) for engaging with the arc-like guide portion (, 213, 523), wherein the engagement portion (215, 525) engages with the guide portion (213, 523) so that the shield plate (205, 503) moves about the pivotal center of the guide portion (213, 523) between a housing position (P201, P501) where the shield plate (205, 503) is housed in the interior of the bowl form of the cap body (203, 507) and a shielding position (P203, P503) where the shield plate (205, 503) covers almost all of the face of the wearer, wherein the shield plate (205, 503) is so constituted as to enter into a space formed between the cap body (203, 507) and the central portion (219, 527) of the guide member (211, 509) to be housed in the cap body. a cap body (203, 507) formed in a bowl form, an opening portion of the cap body being substantially horizontal and the opening portion being positioned at a slightly upper side than the wearer's ears when a standing upright wearer wears the protective cap; a guide member (211, 509) comprising an arc-like guide portion (213, 523), the guide member (211, 509) being so formed in the interior of the bowl form of the cap body (203, 507) and integrally with the cap body (203, 507) that a pivotal center of the guide portion (213, 523) corresponds with an axis (C201, C501) extending in left and right directions through a portion at the rear of ears of the wearer of the cap body (203, 507); and a shield plate (205, 503) formed in a plate form of a transparent material or a translucent material, the shield plate (205, 503) comprising an engagement portion (215, 525) for engaging with the arc-like guide portion (, 213, 523), wherein the engagement portion (215, 525) engages with the guide portion (213, 523) so that the shield plate (205, 503) moves about the pivotal center of the guide portion (213, 523) between a housing position (P201, P501) where the shield plate (205, 503) is housed in the interior of the bowl form of the cap body (203, 507) and a shielding position (P203, P503) where the shield plate (205, 503) covers almost all of the face of the wearer, wherein the shield plate (205, 503) is so constituted as to enter into a space formed between the cap body (203, 507) and the central portion (219, 527) of the guide member (211, 509) to be housed in the cap body.